Cobá was settled much earlier than nearby Chichén Itzá and Tulum, and construction reached its peak between AD 800 and 1100. Archaeologists believe that this city once covered an area of 50 sq km and held a population of 40, 000 Maya.
Cobá’s architecture is a curiosity: its towering pyramids and stelae resemble the architecture of Tikal, which is several hundred kilometers away, rather than the much nearer sites of Chichén Itzá and the northern Yucatán Peninsula.
Some archaeologists theorize that an alliance with Tikal was made through marriage, to facilitate trade between the Guatemalan and Yucatecan Maya. Stelae appear to depict female rulers from Tikal holding ceremonial bars and flaunting their power by standing on captives. These Tikal royal females, when married to Cobá’s royalty, may have brought architects and artisans with them.
Archaeologists are also baffled by the extensive network of sacbés (stone-paved avenues) in this region, with Cobá as the hub. The longest runs nearly 100km, from the base of Cobá’s great pyramid Nohoch Mul to the Maya settlement of Yaxuna. In all, some 40 sacbés passed through Cobá, parts of the huge astronomical ‘time machine’ that was evident in every Maya city.
The first excavation was by the Austrian archaeologist Teobert Maler in 1891. There was little subsequent investigation until 1926, when the Carnegie Institute financed the first of two expeditions led by Sir J Eric S Thompson and Harry Pollock. After their 1930 expedition, not much happened until 1973, when the Mexican government began to finance excavation. Archaeologists now estimate that Cobá contains some 6500 structures, of which just a few have been excavated and restored, though work is ongoing.