The main ridges of the Maya Mountains rise up to the south of Augustine/Douglas Silva, while to the west is the Vaca Plateau, a fantastically isolated wilderness. Sixteen kilometres past the reserve headquarters, the Chiquibul Road crosses the Macal River (and a fault line) over the low Guacamallo Bridge. South of this point, the vegetation changes dramatically: the pines of the northern riverbank change to the broadleaf jungle of the Chiquibul Forest. The turn-off for Caracol is 2.5km past the bridge, and 18km along this road brings you to the visitor centre, where you sign in before exploring the ruins. Many tour operators in San Ignacio run trips to Caracol: Everald Tut has a daily shuttle (US$50 per person; 820-4014). All groups depart for the site by 9am and, due to robberies in the area, travel with a military escort. For a directory of tour operators, see "Tours and tour operators in San Ignacio".

Caracol (daily 8am–4pm; Bz$15), the most extensive and magnificent Maya site in Belize (and one of the largest in the Maya world), was lost in the rainforest for over a thousand years until its rediscovery by chiclero Rosa Mai in 1937. Research has revealed that the name the ancient Maya gave to the city was Oxwitzá, or "three hill water", making this one of the few sites whose true name is known. The locale was first systematically explored by A.H. Anderson in 1938; he renamed the site Caracol – Spanish for "snail" – because of the large number of snail shells he found there. Anderson was accompanied by Linton Satterthwaite of the University of Pennsylvania in the 1950s, but many of their early records were destroyed by Hurricane Hattie in 1961, and several altars and stelae were deliberately broken by logging tractors in the 1930s.

In 1985 the first detailed, full-scale excavation of the site, the "Caracol Project", began under the auspices of Drs Arlen and Diane Chase of the University of Central Florida. Research continues to unearth a tremendous amount of artifacts relating to all levels of Maya society. Over a hundred tombs have been found, one of the best-preserved being B-19, under the largest temple on the summit of Caana. This is almost certainly the tomb of Lady Batz Ek, or "black monkey", who married into the ruling K'an dynasty in 584 AD and who may even have been a ruler in her own right. Other ceremonially buried caches contain items as diverse as mercury and amputated human fingers. There are also many hieroglyphic inscriptions, enabling epigraphers to piece together a virtually complete dynastic record of Caracol's Classic-period rulers from 599 to 859 AD.

Apparently there was a large and wealthy middle class among the Maya of Caracol, and dates on stelae and tombs suggest an extremely long occupation, beginning around 600 BC. The last recorded date, carved on Stela 10, is 859 AD, during the Terminal Classic; evidence points to a great fire around 895 AD. At the height of its dominion, roughly 700 AD during the Late Classic period, Caracol covered 88 square kilometres and had a population estimated at around 150,000, with over 30,000 structures – a far greater density than at Tikal, another important centre of the Maya world. So far, only around ten percent of greater Caracol's full extent has been mapped, and research continues each field season. What continues to puzzle archeologists is why the Maya built such a large city on a plateau with no permanent water source – and how they managed to maintain it for so long.