The strangest image in diving, at 30m you hit a hydrogen sulphide layer that behaves exactly like a cloud bank, and a dead tree…The strangest image in diving, at 30m you hit a hydrogen sulphide layer that behaves exactly like a cloud bank, and a dead tree stands through it with its branches above the 'surface' and its trunk vanishing below. You descend through the cloud into pitch-black saltwater. It looks like a river flowing underwater, and it photographs like a Magritte painting. A collapsed limestone sinkhole in the Yucatán's vast flooded cave network. The cloud forms where fresh rainwater floats on denser saltwater and decaying plant matter produces hydrogen sulphide at the boundary. Angelita became internet-famous through a single photograph and is now a bucket-list dive for photographers. Anchorage: Inland, a shore excursion from a Riviera Maya or Cozumel anchorage. Hazards: No site-specific hazards noted, brief normally. Altro