The oldest merchant ship ever discovered is a wreck, to be sure, but a beautifully preserved one. It lies on its side at the bottom of the Black Sea, where low-oxygen waters a mile deep have protected it from divers and decay since around 400BC.

The discovery comes thanks to scientific ­advances in marine archaeology, especially imaging techniques, but also to the fact that the offshore ­services market has been far under water for such a long time.