Pamukkale Travertine Terraces, Turkey

The 'cotton castle'

It's not hard to see where these travertine terraces in Türkiye got their name: Pamukkale, meaning 'cotton castle' in Turkish. In bright daylight, these huge stair-steps of puffy, porous limestone appear cloud-white, their multilevel pools a dazzling shade of sky blue. When the basins are full of hot spring-fed water, it's a fine place to relax after visiting neighboring Hierapolis for a dose of ancient history.