Amphora scatters and the stonework of an ancient harbour in shallow water off a peninsula town founded by Greek colonists in…Amphora scatters and the stonework of an ancient harbour in shallow water off a peninsula town founded by Greek colonists in the 7th century BC, plus the shallow seagrass of Seahorse Alley, where the Black Sea's seahorses live in under seven metres. Apollonia Pontica, now Sozopol, was one of the oldest Greek colonies on the Black Sea and its harbour silted and sank over the centuries. Below about 150m the whole Black Sea is anoxic, which is why its deep wrecks, including a 2,400-year-old Greek trader found intact in 2018, are the best preserved on earth. Anchorage: Sozopol has a marina and two sheltered bays, and is the natural first stop south of Burgas on the Bulgarian coast. Hazards: Antiquities that must be left in place, and summer boat traffic in the bays. Plus