How Maya cities have stood for millennia

Getty Images

Constructed complete 1,200 years ago, nan imposing 65m-tall (213ft) Temple IV astatine Tikal, successful modern Guatemala, is simply a testament to ancient Maya masonry (Credit: Getty Images)

Ruins of ancient cities support turning up successful nan forests of cardinal America. How person these structures remained opinionated for millennia contempt tropical rains, hurricanes and nan return of nan jungle?

Anyone driving down nan unsmooth asphalt of road 269 that bisects nan Yucatán peninsula successful southeast Mexico would ne'er person known it was there. Thick jungle lines some sides of nan roadworthy for overmuch of its length, pinch nan occasional spot cleared for livestock. Yet, aft an innocuous crook successful nan road, adjacent to nan mini colony of Dos Lagunas, an full metropolis has been hiding.

Concealed beneath a tangle of trees, vines and different vegetation, scientists person discovered a sprawling postulation of houses, plazas, temple pyramids and moreover a ballcourt utilized for shot games that person nan "hallmarks of a Classic Maya governmental capital". The remains of nan city, which nan researchers person named Valeriana, are among 6,674 structures they recovered scattered successful sites crossed nan authorities of Campeche connected nan occidental broadside of nan Yucatán peninsula. Some of nan largest platforms whitethorn moreover rival much celebrated pyramids astatine different Maya sites.

The find – made utilizing an airborne laser scanning method called ray discovery and ranging, aliases Lidar – has raised nan tantalising imaginable that galore much remains of nan ancient Maya world whitethorn still beryllium waiting to beryllium found.

But it besides reveals thing bonzer astir nan ancient Maya world. Despite nan humid tropical ambiance and nan enveloping clasp of nan jungle, galore of their buildings are still opinionated aft 1,500 years.

"If you look astatine nan integer terrain models that are produced by Lidar, you tin spot nan individual rooms of buildings wherever nan vaults person collapsed," says Luke Auld-Thomas, an archaeologist astatine Tulane University and Northern Arizona University, USA, who led nan squad that made nan latest discovery. "You tin spot columns on nan destruction of buildings that were utilized for nationalist facing, administrative activities. So they're really successful very bully shape. You couldn't rather move into them, but a batch of them still person opinionated walls and architectural item that's rather good preserved."

So, what was nan ancient Maya's secret? How has their celebrated architecture withstood nan ravages of time? Recent investigation is shedding ray connected nan techniques their builders utilized and revealing nan innovative attack their masons used. These see incorporating materials specified arsenic rubber into mortars to enactment arsenic an adhesive, and volcanic ash to summation their strength.

Getty Images

The structures of nan ancient Maya were built to past against nan elements (Credit: Getty Images)

The ancient Maya civilisation first emerged sometime earlier 2000BC successful an area that coming comprises south-eastern Mexico, Guatemala, Belize and nan occidental portions of Honduras and El Salvador.

During nan Classic Period of Maya civilisation betwixt 250 to 900 AD, nan Maya constructed towering pyramid temples, beautiful palaces and finely dressed up buildings adorned pinch intricate sculptures and ornately carved masks. Notable examples see Chichén Itzá, a tract successful Yucatán, Mexico, which boasts astatine its bosom a 30m-high (98ft) pyramid called nan Temple of Kukulcán. There is besides Temple IV, a 65m-tall (213ft) pyramid successful nan ruins of nan ancient Maya metropolis of Tikal in modern Guatemala.

In nan past, uncovering a Maya metropolis progressive wading done heavy jungle and hacking done vegetation pinch a machete. But exertion specified arsenic Lidar is now helping to uncover conscionable really wide nan remains of ancient Maya settlements really are.

Juan Carlos Fernandez-Diaz, an technologist astatine nan University of Houston, Texas, who was progressive successful nan latest study, has been mapping areas successful Mesoamerica – including Mexico, Guatemala, El Salvador and Honduras – pinch Lidar for nan past 15 years. He says that almost wherever you look you tin spot good preserved Maya architecture.

Recent discoveries see nan oldest and largest Maya ceremonial structure, which was uncovered astatine nan archaeological tract of Aguada Fénix successful Tabasco, Mexico successful 2020. The long, rectangular elevated level measures 1,400m (4,593ft) successful magnitude and 10-15m (33-49ft) successful height. It was built from clay and world betwixt 1,000 to 800 BCE and was apt utilized for ceremonial rituals.

A abstracted squad utilized Lidar to uncover a massive Maya site that stretches astir 650sq miles (1,700sq km) crossed bluish Guatemala. The scientists spotted 1,000 settlements connected to each by roads that nan Maya apt traversed connected foot.

"As we get to representation much and much of nan Yucatán, we fundamentally cognize that if you propulsion a dart astatine nan map, wherever that dart falls location will beryllium immoderate benignant of Maya infrastructure connected it," says Fernandez-Diaz.

Part of nan logic these discoveries are opinionated astatine each is because nan ancient Maya built pinch stone, which does not rot distant for illustration wood. But they were besides peculiarly bully astatine making mortar to forestall their chromatic structures from crumbling into piles of rubble.

Studies person shown that ancient Maya builders utilized a scope of natural materials specified arsenic blood, eggs and earthy rubber obtained from section trees erstwhile preparing mortar. For example, erstwhile successful 2018 researchers analysed mortar taken from stones astatine nan main pyramid astatine nan Witzinah archaeological tract adjacent Yucatán, Mexico, they recovered traces of saturated fats emblematic of degraded earthy rubber. The researchers judge nan Maya masons obtained nan rubber from section trees and utilized it arsenic a binder on pinch a fine-grained clay to create a durable mortar to hindrance nan stonework together.

A abstracted study successful 2014 examined mortar samples from nan archaeological tract of Río Bec successful south-eastern Campeche, uncovering grounds that Maya chromatic masons added volcanic ash to nan mortar to fortify it.

Perhaps moreover much astonishing than their chromatic structures, however, is nan preservation of dressed up plasters that person besides been discovered successful immoderate locations. Scientists person known for immoderate clip that nan ancient Maya knew really to make lime plaster, which they utilized to overgarment and protect interior floors aliases wall surfaces, hindrance stones together and screen and decorate nan aboveground of chromatic buildings. Examples of intricately dressed up plaster-covered buildings tin still beryllium seen successful Tikal and Copan, an ancient Maya tract successful Honduras, today.

As portion of his study, Rodriguez-Navarro's squad met pinch section chromatic masons successful nan area and asked them astir their techniques for making lime mortar. The masons, who are nonstop descendants of nan ancient Maya, said that they commonly usage extracts from plants and peculiarly sap from nan Chucúm and Jiote (Chaká) trees successful their lime mix.

Next, nan researchers analysed nan ancient plaster from nan Honduras tract and prepared a replica of it. The process of making plaster involves baking (calcinating) carbonate stone worldly specified arsenic limestone utilizing basking temperatures, earlier adding h2o to nan resulting quicklime, forming a lime paste which is mixed pinch sand. As nan worldly hardens it sucks c dioxide from nan air, trapping it successful nan calcite cement. The researchers besides took nan proposal of nan chromatic masons and added juice from nan bark of Chucúm and Jiote trees to nan mix. They recovered that nan resulting plaster was particularly hardy and durable.

"We were capable to precisely replicate nan structure, texture and mechanical properties of nan ancient material," says Rodriguez-Navarro.

Getty Images

Maya chromatic masons utilized sap from trees specified arsenic nan Jiote (Bursera simaruba) to thief harden their lime mortar (Credit: Getty Images)

The scientists past analysed nan original plaster utilizing precocious solution X-ray diffraction, a method that enabled them to position nan worldly astatine nan atomic scale. The results showed that molecules of nan integrated worldly from nan bark had go incorporated into nan molecular building of nan lime plaster during nan setting, aliases hardening process. According to Rodriguez-Navarro, this makes nan worldly very durable and resistant to beingness and chemic weathering.

"It's very difficult to break nan material, because it is simply a composite betwixt integrated and inorganic materials," says Rodriguez-Navarro. "So, if you effort to break nan purely inorganic calcite it is very elemental – it's fragile, truthful you conscionable deed it, and it collapses. But if you incorporated nan integrated atoms from nan character sap you make nan worldly tougher. So, nan power you person to walk to break that worldly is really, really high."

The incorporation of integrated works worldly besides makes nan worldly much insoluble, which prevents it from dissolving successful nan rainfall – an important characteristic successful nan tropical ambiance that is often buffeted by hurricanes bringing dense rain.

Other studies astatine sites specified arsenic Ek'Balam successful Yucatán, Mexio, besides recovered that extracts from different character – pixoy, aliases Guazuma ulmfiolia – helped to enactment arsenic a fixative to sphere nan layers of colour utilized successful nan lime-plaster.

There is, of course, different logic why nan ruins from abandoned Maya cities whitethorn person lasted arsenic agelong arsenic they person – nan jungle itself. Although nan trees person made nan ruins difficult to find, they person besides protected them from being built complete and looted.

"There are parts of nan world wherever group person bulldozed pyramids to usage arsenic roadworthy fill, aliases because they're successful nan measurement of wherever they want to tally cattle," says Ault-Thomas. "However, it's difficult to do that erstwhile location are a gazillion trees successful nan way."

Getty Images

Many of nan cities built by nan Maya had plazas and areas reserved for playing shot games (Credit: Getty Images)

The Maya besides transformed nan scenery astir their settlements to thief protect them from nan ravages of water. Auld Thomas saw grounds of this astatine nan tract of Valeriana he helped to discover.

"It's besides successful an area that's extensively modified for agriculture," he says. "It's rather hilly, and fundamentally each sloping aboveground that is supra nan level of seasonal flooding is sculpted, terraced and wholly reworked truthful that group could usage it to turn nutrient and support their feet barren successful nan rainy season."

So, could modern societies study thing from these ancient Maya builders erstwhile it comes to creating cities that are resilient to ambiance change?

"The Maya lawsuit really shows that it's imaginable to negociate nan scenery successful a measurement that allows it to past and thrive for a millennium, moreover successful reasonably utmost environments wherever it doesn't rainfall for half nan year, but past rains each time for nan different half of nan year," says Auld-Thomas.

We could study from nan Maya's prime of materials too. The reinforced actual recovered successful astir modern buildings is beardown capable to clasp up monolithic skyscrapers, but they aren't built to last. The lifespan of astir alloy reinforced concrete buildings is astir 50 to 100 years. At nan aforesaid time, cement accumulation presently accounts for 8% of world c emissions – acold much than aviation.

Some researchers are looking to lime-based alternatives to cement. Currently, lime accumulation is simply a major root of c dioxide emissions, but immoderate researchers are investigating obtaining it from different sources, specified arsenic nan by-products of nan insubstantial industry, for example, which whitethorn make it much sustainable. Drawing connected nan knowledge of nan ancient Maya arsenic inspiration could thief to make specified materials much durable, says Rodriguez-Navarro.

Lime mortars tin also enactment arsenic a c sink, absorbing c dioxide from nan aerial arsenic they remineralise and harden into limestone.

"Lime is attracting a batch of attraction arsenic a imaginable sustainable worldly for modern construction," says Rodriguez-Navarro. "Not only will it suck up CO2 during carbonation, but astatine nan aforesaid clip you get a very durable worldly if you adhd nan due integrated additives."

--

If you liked this story, sign up for The Essential List newsletter – a handpicked action of features, videos and can't-miss news, delivered to your inbox doubly a week. 

For much science, technology, situation and wellness stories from nan BBC, travel america connected Facebook, Xand Instagram.