From an island in Singapore to an all-inclusive eco-stay in Mexico, here are 10 top sustainable places to holiday this Earth Day Every April 22, the world celebrates Earth Day and while travel and sustainability don't always go hand in hand, it's a sector of the travel market that's rapidly expanding. The travel experts at Expedia have analysed thousands of customer reviews to put together a report that details the top 10 sustainable places to stay around the world. Singapore