Welcome to Lago de Atitlán
Though volcanic explosions have been going on here for millions of years, today's landscape has its origins in the massive eruption of 85,000 years ago, termed Los Chocoyos, which blew volcanic ash as far away as Florida and Panama. The quantity of magma expelled from below the earth's crust caused the surface terrain to collapse, forming a huge, roughly circular hollow that soon filled with water – the Lago de Atitlán. Smaller volcanoes rose out of the lake's southern waters thousands of years later: Volcán San Pedro (today 3020m above sea level) about 60,000 years ago, followed by Volcán Atitlán (3537m) and Volcán Tolimán (3158m). The lake today is 8km across from north to south, 18km from east to west, and averages around 300m deep, though the water level has been on the rise since 2009.
Around 900 AD, when the Maya highland civilization was in decline, the region was settled by two groups that had migrated from the Toltec capital of Tula in Mexico, the Kaqchiquel and Tz'utujil. The latter group settled at Chuitinamit, across the way from the present-day village of Santiago Atitlán, while the former occupied the lake's northern shores; this demographic composition persists to this day. By the time the Spanish showed up in 1524, the Tz'utujil had expanded their domain to occupy most of the lakeshore. Pedro de Alvarado exploited the situation by allying with the Kaqchiquels against their Tz'utujil rivals, whom they defeated in a bloody battle at Tzanajuyú. The Kaqchiquels subsequently rebelled against the Spanish and were themselves subjugated by 1531.
Today, the main lakeside town is Panajachel, or 'Gringotenango' as it is sometimes unkindly called, and most people initially head here to launch their Atitlán explorations. Santiago Atitlán, along the lake's southern spur, has the strongest indigenous identity of any of the major lake towns. Up the western shore, the town of San Pedro La Laguna has a reputation as a countercultural party center. On the north side, San Marcos La Laguna is a haven for new-agers, while Santa Cruz La Laguna and Jaibalito, nearer to Panajachel, are among the lake's most idyllic, picturesque locales.
The lake is a three-hour bus ride west from Guatemala City or Antigua. There is an ersatz town at the highway junction of Los Encuentros, based on throngs of people changing buses here. From La Cuchilla junction, 2km further west along the Interamericana, a road descends 12km southward to Sololá, and then there's a sinuous 8km descent to Panajachel. Sit on the right-hand side of the bus for views of the lake and its surrounding volcanoes.