You will find shipwrecks of varying vintage in the list that follows, but there are other locations in which to seek out submerged history. These are hidden places, where the natural processes of decay have been stalled by water. 
Here, then, is my guide to time travel by scuba (or snorkel), beginning 5,000 years ago in ancient Greece.

Pavlopetri City, Peloponnese, Greece (3,000 BC)

The extensive underwater ruins of Pavlopetri are believed to be about 5,000 years old, making it the oldest known underwater city. The site is shallow, basking in the clear water and bright sunlight of the Ionian Sea. As it is an ancient site, all signs of ­settlement have been subsumed into what looks initially like a series of shallow reefs and gullies. Still, even to the untrained eye it becomes evident that the array of raised walls, avenues and enclosures represents the remains of a bygone civilisation. First discovered by marine geo-archaeologist Dr Nicholas Flemming in 1967, it is thought the city was flooded by the first of three earthquakes. The area could never be resettled, so what remains in that azure water represents a frozen snapshot of its time.

Dive in: Due to the site’s designation as a Unesco park, full scuba gear is not permitted. Not a problem, as all you need for the shallow ruins are mask, fins and snorkel. You can access the site at Pavlopetri Beach and simply stroll into the water, but remember the strict rule – do not touch any structures or artefacts 

Amphora wrecks, Croatia (200 AD)

When Roman-era ships sank in Mediterranean storms, their wooden hulls and decks were eaten away by shipworm, leaving clusters of stacked amphorae. These hefty ceramic containers were used for the transportation of olive oil, wine and the fish sauce Romans used as a piquant relish.

The northern side of Host, an island in Vis Bay, has two amphora wrecks dating from the 2nd century. Though a fair number of the chunky jars have broken up in storms, their formation conjures up the space they once occupied in the ghost-hold of the wooden ship that has now rotted away.