AT A GLANCE
Why go?
Tenorio Volcano National Park (Parque Nacional Volcán Tenorio) sits in Costa Rica's northern lowlands, a rainforest-swathed volcanic massif best known for one astonishing sight: the Río Celeste, a river that runs an almost unreal shade of turquoise. The park takes its name from the dormant stratovolcano at its heart, but the experience visitors come for is the electric-blue water, which you follow up a single jungle trail to a thundering waterfall, geothermal bubbling vents and the exact point where the colour is born.↗↗
This is not a summit climb but a linear rainforest walk — the roughly 3 km "Misterios del Tenorio" trail (about 6 km round trip, three hours or more) links the park's wonders in sequence. It draws enormous numbers of visitors and carries a 4.6 rating on thousands of reviews, because the payoff, the Río Celeste Waterfall plunging into a pool of brilliant blue, is genuinely one of Costa Rica's signature landscapes.↗↗
A river the colour of a painted sky
Local legend says that after God finished painting the sky He rinsed His brushes in the Río Celeste, and the river has been that shade of blue ever since. The real explanation is no less remarkable. Researchers from the University of Costa Rica and the National University found the colour is an optical effect rather than a chemical dye: a fine white aluminosilicate mineral coating the riverbed scatters sunlight so that the water reads as glowing turquoise. It is why the river can look perfectly clear in one stretch and impossibly blue in the next.
