Mesharifa

From August into autumn, plankton concentrates in the channels around Mesharifa's small sand island, and reef manta rays arrive to work it - looping, barrel-rolling, mouths agape, sometimes in feeding chains a dozen animals long. The water is shallow and the action often happens at the surface, so this is chiefly a snorkel encounter, drifting quietly while the mantas commute their invisible plankton lanes; dives along the channel edges add rays, turtles, and the odd passing eagle ray. The site sits inside the Dungonab Bay side of Sudan's World Heritage marine park, and its aggregation is the country's gentlest marquee event - no depth, no current games, just abundance. Boats historically timed their final itineraries of the hot season around it.

The moment you come for: Feeding chains of reef mantas; surface encounters in warm, easy water; the wild north of Sudan's marine park.

Topography: Shallow lagoon channels and sand flats around a low sand island

Entry: A sandy islet lagoon in the Dungonab Bay area, far north of Port Sudan; visited on late-summer itineraries built around the mantas.

Hazards: Sun and heat in the peak manta months; shallow sand bars around the lagoon.

Conservation: Approach mantas from the side, never over their line of travel, and let feeding animals set every distance.