One place of Bodrum that no visitor to this great city should miss is the famous Bodrum Castle, which overlooks the harbor and the international marina. This castle was constructed by the Knights of Rhodes in the 15th century during the crusades of the middle ages, and it was given the name The Castle of St. Petrus, or Petronium.
Occupying over 30.000 square feet at its base, construction of this castle took years to complete. The castle was built partly from the left remains of the mausoleum of Mausolus which had collapsed as the result of an earthquake. The huge exterior walls were designed in the early 15th century by the German architect Heinrich Schlegelholt and were strengthened by five towers known usually as the English tower, the Italian tower, the German tower, the French tower and the Snake tower. The French tower of the castle is thought to be the earliest one with the others being added during the following century. After the French Tower The Italian tower was built in 1436 by Italian architect Angelo Mascettola. The final parts of the castle were erected in the time of Pierre d'Abusson between 1476 and 1593, with the English tower being added at around 1480.
The walls of the Bodrum castle contain the nearly 250 coats of arms and armorial bearings of many of the knights that served there. Captured in 1522 by the Ottomans during the reign of Kanuni Sultan Suleyman, the church on the castle was converted into a mosque. Bodrum Castle has a square-like plan. The castle's dimensions are 590 x 606 feet (180x185 m), and it's highest point is 155.8 feet (47.5 m) above sea level. The entrance of the castle is through the first door situated in the northwestern corner. There are 7 doors before you reach the inner castle. The northern and western sides are double-walled. The thick walled structure with a sloping roof at the west side is a cannon blockhouse. All the towers and various places in the Castle of Bodrum have been converted into exhibition halls for the Underwater Archaeology Museum. The Bodrum Castle is open to the public and it houses Bodrum's remarkable Museum of Underwater Archaeology.