Tikal

Tikal, in the rainforest of Guatemala's Petén region, was one of the most powerful city-states of the ancient Maya civilisation, dominating much of the central Maya lowlands during the Classic Period (roughly 200–900 CE). At its peak the city supported a population estimated at up to 90,000 people and is dominated by six steep-sided pyramid temples, the tallest — Temple IV — rising about 70 metres above the forest floor, among the tallest pre-Columbian structures in the Americas. Decades of epigraphic research, particularly from the 1960s onward, have allowed scholars to reconstruct a dynastic sequence of more than 30 rulers spanning roughly 800 years, including a documented military defeat in 562 CE by the rival city of Calakmul that triggered a "hiatus" of over a century in monument construction at Tikal — a dark age in the city's own historical record from which it eventually recovered to enjoy a final resurgence in the 7th and 8th centuries.

Like most lowland Maya cities, Tikal was largely abandoned by around 900 CE during the broader "Classic Maya collapse," a still-debated phenomenon for which researchers have proposed causes including prolonged drought (supported by lake-sediment studies showing severe dry periods in the relevant centuries), warfare between competing city-states, and overpopulation leading to agricultural and environmental degradation — likely some combination of all three. The site was reclaimed by jungle and remained known mainly to local Indigenous communities until the mid-19th century, when reports of the ruins reached the outside world and prompted the first formal expeditions; large-scale excavation and restoration began only in the 1950s, and Tikal became one of the first sites in the world to be inscribed on UNESCO's World Heritage List for both its cultural and natural significance, in 1979.