Notable sites include Chichen Itza, Palenque, Uxmal and Yaxchilan in Mexico, Tikal in Guatemala and Copán in Honduras.
In the northern Petén lowlands of Guatemala there are several sites, and Tikal is the most famous.
In Guatemala, they say, tunnels have been mapped under the Maya pyramid complex at Tikal, running a full 800 kilometers to the other side of the country.