Aydos Castle, located in the Pendik district on Istanbul’s Asian side, stands as one of the city's most important historical landmarks. The castle dates back to the Byzantine era, though it was later expanded and fortified during the Ottoman period. Originally built for defensive purposes, the castle offers panoramic views of the surrounding area, including the Aydos Forest and the Marmara Sea in the distance. Today, Aydos Castle is a popular destination for history enthusiasts and nature lovers alike. The site is surrounded by a peaceful park, making it a perfect spot for hiking and picnicking. Although the castle is in a state of partial ruin, its strategic location and historical significance continue to draw visitors, offering a glimpse into Istanbul’s rich past while providing a tranquil escape from the city.