Paleo Pyli Castle is a historical landmark located in the village of Paleo Pyli, on the island of Kos which was built in the 14th century by the Knights of Saint John, a military order that controlled the island during the Middle Ages. 

The castle was strategically placed on a hilltop, giving it an advantage for defense against enemy attacks. 

Today, the ruins of the castle still stand, including the outer walls and several towers. While much of the castle has deteriorated over the years, visitors can still explore the site and experience the rich history and stunning views from the top of the hill. 

In addition to the castle, visitors can also explore the nearby village of Paleo Pyli, which features charming traditional architecture and a quaint village square.