Gebze

"Eski" means old and "hisar" means fortress, and there's been a castle on this site since the 12th century, the Byzantine era. It's been turned into an open-air theatre, access at other times is erratic.

A charming 19th century wooden mansion, the summer home of Osman Hamdi Bey (1842-1910), the polymath founder of the Istanbul Archaeology Museum and one of the earliest modern Turkish painters. His best known painting is "The Tortoise Trainer", satirising attempts to reform the Ottoman Empire.

Established in 1845, this was the imperial factory which laboriously produced the unconventionally large carpets embellishing late Ottoman palaces of Istanbul, and other contemporary imperial courts elsewhere. Just across the street, right on the water, is the Kaiser Wilhelm II Mansion, a wooden building prefabricated in Istanbul and assembled here in just one day to accommodate the German emperor on his 1884 visit to the factory.

The 7th-century, Roman-built castle fell into ruin during the heavily destructive 1509 earthquake. It was rebuilt in 2023, and has nice views over the town and the sea.