The southern beaches of Sri Lanka lie on the very edge of the vast Indian Ocean. From almost every vantage point on the private resort of Ani – your equally vast bed, the two infinity pools, the many palm-fringed decks – the third largest basin of water on Earth spills out beneath you. Sometimes ghostly container ships break the horizon, but beyond that is nothing, no landmass for more than 7,000 miles until the Southern Ocean meets the shores of Antarctica.