1½ hours’ drive from San Jose, the huge turquoise lake and smouldering caldera of Poás Volcano is one Costa Rica’s most impressive (and photographed!) sites. The beautiful colour belies its true nature as one of the world’s most acidic lakes and visitors are often treated to its sulphuric fumes and geyser-like mini-eruptions. Close by, Poás second crater lake “Lago Botos” is surrounded by dense vegetation and dwarf cloudforest that harbours interesting birdlife including toucanets and quetzals. The national park is a popular daytrip from the capital yet stay a night in one of the surrounding lodges and you can hike down to Lake Botos and the extinct Von Frantzuis crater well away from the usual tourist groups.