Cottage Pond Turks & Caicos

This tropical blue hole (43m deep), formed by karst subsidence, is fed by the tides and connects to a much larger underground chamber. While it's not visually spectacular, it's interesting and a good place to spot West Indian whistling ducks, grebes, waders and other waterbirds. Look for the unobtrusive turnoff on Sandy Point Rd, about 1.2km from the T-junction with Kew Hwy.