La Palma, one of the lesser-known Canary Islands, is the world’s steepest island (based on the ratio of its area – 708sq km – to its highest point – 2,423m). Known as ‘la isla verde’, the green island, it’s the lushest of the archipelago, with tropical flowers, cloud forest, palms and pines, Insta-worthy cacti and succulents – and endless banana plantations. The capital, Santa Cruz, on the east coast near the airport, has solid stone colonial architecture – churches, museums and municipal buildings – and a couple of streets of houses with traditional wooden balconies overflowing with flowers. Dominating the north is the 8km-wide crater of the Caldera de Taburiente. Caldera, which means cauldron, has been used for all volcanic craters since German geologist Christian Leopold von Buch used it after his 1815 visit. La Palma hasn’t suffered from over-development like some of its neighbours, so fewer bars and clubs and more focus on outdoor activities like appreciating the beauty of the natural landscape, hiking and biking and swimming. (Take beach shoes; those black-sand beaches are blisteringly hot.) By night, lift your eyes to the skies: the island is a Starlight Reserve, and some of the world's largest telescopes are sited here.