Arenal Volcano rises 1,633 meters above the surrounding lowlands, its near-perfect cone dominating the skyline from every street in town. For decades after the 1968 eruption, Arenal was one of the most consistently active volcanoes in Central America, producing lava flows that glowed orange against the night sky and drew scientists and tourists in roughly equal numbers. That spectacle ended around 2010, when the volcano entered a period of dormancy that continues today. The lava no longer flows, but the geological forces that powered it still heat the water beneath the surface. Hot springs emerge along the volcano's northern slope, where streams of volcanically heated water mix with cool rainforest runoff. During the dry season, these springs offer crystalline soaking pools. In the rainy season, the thermal waters carry a higher bacterial load as cold rainwater dilutes the heat -- a tradeoff the locals know well.

La Fortuna is defined as much by its water as by its volcano. Lake Arenal, an 85-square-kilometer reservoir enlarged to its current size in 1979 when the Costa Rican government completed the Presa Sangregado Dam for hydroelectric power, stretches along the volcano's southwestern flank. The lake holds Guapote bass -- a close relative of the peacock bass and equally aggressive -- alongside the Mojarra, a fruit-eating fish sometimes compared to piranha. The Rio Toro, running through deep canyon gorges to the east, offers Class 3-4 whitewater rapids that cut past waterfalls draped in tropical vegetation. The more forgiving Rio Balsa provides Class 2-3 runs for those who prefer their rapids without the adrenaline spike. Even the town's signature waterfall, La Fortuna Waterfall, drops roughly 70 meters through a jungle amphitheater that requires a steep descent of over 500 steps to reach the plunge pool below.

La Fortuna's transformation from farming village to tourism hub has been swift and total. The main street is lined with tour agencies, souvenir shops selling photos of the erupting volcano, and restaurants bearing names like Lava Lounge and Lava Rocks. Locals joke that Fortuna is the tout capital of Costa Rica -- a place where every "tourist information center" is actually a tour operator and every friendly conversation on the street has a sales pitch embedded in it. The hustle is relentless but not unfriendly. Budget travelers who resist the upsell can organize most activities independently: hitching a ride to the park entrance, walking to free hot spring pools along the river, and eating at local sodas where a plate of rice, beans, salad, and meat costs around 3,000 to 4,000 colones. The trick, seasoned visitors say, is knowing that most of what the tour companies sell for $50 or more can be assembled for a fraction of the price with a bus schedule and some patience.

La Fortuna sits at a geographic crossroads in northern Costa Rica, roughly three and a half hours by car from San Jose. Direct buses make the five-and-a-half-hour run from the capital, and domestic airlines connect the town to San Jose and Quepos. But the most storied route out of La Fortuna runs southwest toward Monteverde, the cloud forest reserve on the continental divide. Travelers can ride horseback for two and a half hours along the shore of Lake Arenal, crossing between the tropical lowlands and the misty highlands in a single afternoon. The route reverses an older pattern -- for generations, the Arenal region was the backwater and Monteverde was the destination. Now traffic flows both ways, and La Fortuna has become its own center of gravity. From here, the road north leads to the Cano Negro Wildlife Refuge near the Nicaraguan border, and the road west connects through Tilaran to the Guanacaste coast.