The Crusader castle of Saint Peter the Petronium from which the name Bodrum is derived - dominates the town as it has done for more than 500 years. Built by the Knights of Saint John in the early 1400s, the castle also houses the Museum of Underwater Archaeology, the largest built for a single archaeological display in Turkey and funded by the Ministry of Culture.

One of the finest examples of Crusader architecture in the east, it was built from materials taken from the nearby Tomb of King Mausolus, one of the Seven Wonders of the ancient world. And over the gates and in the walls, fragments of the Mausoleum can still be seen. All that remains of once magnificent tomb are mar columns and foundation blocks.

The Museum of Underwater Archaeology is in the inner castle, reached after passing through seven gates embellished with coats of arms and inscriptions. Opened in the 1960s by Dr George Bass, the eminent nautical archaeologist, it now has fascinating finds from seven shipwrecks from the Bronze Age to the Byzantine Empire.

Recognized as one of the finest museums of its kind in the world, there is a collection of artefacts from the Cape Gelidonya wreck, Bass's first excavation. AD the finds are carefully labelled and exhibited. They include the Seytan Deresi wreck in Gokova Bay, the Musgebi land excavation in a necropolis which has yielded the richest Mycenaean collection outside Greece, and the "glass wreck" found in the small natural bay called Serce Harbor, near Marmaris.

This memorable exhibition of glass objects and fragments were part of the cargo of a ship, which sank in Serce Harbor in 1025 AD. It was originally thought that the glass had shattered when the ship met its violent end. This proved incorrect and it is now believed that it was broken glass intended for recycling.

The delicate, multicoloured glass fragments have been painstakingly reconstructed by specially trained workers into exquisite cups, bottles and plates, many with designs in relief.

A permanent staff of archaeological cataloguers and conservators, augmented by American university students in the summer, work on the finds from the wrecks. When huge remains such as ship hulls are found, reconstruction can mean full-time work for several years.