8. Tsingy de Bemaraha, Madagascar
In Malagasy ‘tsingy’ translates loosely as ‘walking on tiptoes’ – a natural fit for one of the world’s spikiest landscapes. A massive ‘forest’ of limestone needles and razor-sharp ramparts, Tsingy de Bemaraha was carved by millennia of unusual erosion, and now looks more like Mordor than the neighbouring rainforests. Madagascar is renowned for endemic species (90% of its fauna are found nowhere else), and even this inhospitable ecosystem houses unique species of lizard, lemur and frog. Not one to visit in flip flops.