Laguna Caliente, Costa Rica
Located high up on Poas, an active volcano in Central Costa Rica, Laguna Caliente’s bright blue waters are a spectacular sight. Do come here and take a look. Don’t be tempted to take a dip.
This is a crater lake hazardous to health, its waters amongst the most acidic on Earth, where little or no aquatic life is found, and those who get too close are exposing themselves to significant dangers.
The acid gases that rise up from the lake can irritate eyes and lungs, whilst there’s always the chance that Poas could explode. There have been 40 eruptions here since 1828 — the last in 2017, when visitors had to be evacuated and the National Park closed for almost 18 months. Despite the dangers, Laguna Caliente calls to the curious. Can’t keep away? That’s fine — but remain a safe distance and don’t even think about swimming here.