The first volcanic activity in this region began roughly 11 million years ago, but the event that created the basin holding Lake Atitlan was far more recent and spectacularly violent. Known as the Los Chocoyos eruption, it ejected up to 300 cubic kilometers of tephra and dispersed ash across six million square kilometers -- an eruption so massive that its deposits serve as a stratigraphic marker in both the Pacific and Atlantic oceans, cataloged as Y-8 ash in marine sediments. The caldera that collapsed in its aftermath gradually filled with water, and three new volcanoes grew from its floor: San Pedro, the oldest, which stopped erupting roughly 40,000 years ago; Toliman, which likely remains active though it has never erupted in recorded history; and Atitlan, the youngest and most restless, whose last eruption came in 1853. On February 4, 1976, a magnitude 7.5 earthquake fractured the lake bed, causing the water level to drop two meters in a single month as water drained through new subsurface cracks.

The lake's surface area spans 130 square kilometers, surrounded by villages where Maya culture remains the dominant thread. The Tz'utujil people live along the southern and western shores; the Kaqchikel inhabit the northern communities. The two groups speak different but related Mayan languages, and their histories intertwine in complicated ways -- during the Spanish conquest, the Kaqchikel initially allied with the invaders to defeat their Tz'utujil and K'iche' rivals, only to be conquered themselves when they refused to pay tribute. No road circles the lake. Communities connect by boat or by mountain roads with brief shoreline extensions. Jaibalito can only be reached by water. In the late mornings and afternoons, a wind called Xocomil sweeps across the surface, generated when warm Pacific air collides with colder northern currents. In the Kaqchikel language, the name means "the wind that carries away sin." It can also capsize boats.

Santiago Atitlan, the largest lakeside community, is the center of worship for Maximon, an idol born from the fusion of traditional Maya deities, Catholic saints, and conquistador legends. A local religious brotherhood controls the effigy, which moves between members' houses throughout the year and processes through town most dramatically during Semana Santa. Panajachel, on the northern shore, took a different path. It attracted hippies in the 1960s, and though the civil war drove many foreigners away, the end of hostilities in 1996 brought tourism flooding back. Today Panajachel's economy depends almost entirely on visitors. Beneath the lake itself, about 55 feet below the current water level, divers have found the remains of Samabaj, a ceremonial site from at least the pre-Classic period, with multiple building groups including what appears to have been a city center. The site held deep spiritual significance, connected to the Popol Vuj of the K'iche' Maya.

During the Guatemalan Civil War, which raged from 1960 to 1996, the lake communities suffered terrible human rights abuses. The government pursued a scorched-earth policy, assuming indigenous people universally supported the guerrillas fighting in the nearby mountains. In 1981, Stanley Rother, a Catholic missionary from Oklahoma, was assassinated in the church at Santiago Atitlan. In 1990, townspeople marched to the local army base in protest; soldiers opened fire, killing 14 unarmed civilians. International pressure forced the government to close the base and declare Santiago Atitlan a military-free zone. Fifteen years later, Hurricane Stan buried the lakeside village of Panabaj under a massive landslide, killing as many as 1,400 people and leaving 5,000 homeless. The mayor declared the buried village a permanent cemetery.

In 1958, Pan American World Airways suggested stocking Lake Atitlan with black bass to attract sport fishermen and boost tourism. The bass adapted aggressively, eliminating more than two-thirds of the lake's native fish species and contributing to the extinction of the Atitlan grebe, a flightless waterbird found nowhere else on Earth. The chocoyo -- a small parakeet that nests in the soft volcanic ash -- gave the caldera-forming eruption its name, but it was the grebe that became the lake's most poignant ecological loss. In 2009 and again in 2015, blooms of Microcystis cyanobacteria spread across the water, fed by untreated sewage and agricultural runoff. The lake that Huxley called too much of a good thing faces the prospect of becoming too degraded for human use. Coffee orchards, corn fields, and avocado groves still sustain the largely indigenous population around its shores, but the balance between beauty and burden grows more precarious each year.