The Atik Valide Mosque (Turkish: Atik Valide Camii) is a historical mosque in Istanbul, Turkey. It is located in the Üsküdar neighbourhood of the city, on the Asian side of the Bosphorus Strait, and is known for its beautiful architectural features and rich history. 

The Ottoman architect Mimar Sinan built the mosque in the mid-16th century on the orders of the Ottoman princess Atik Valide, the mother of sultan Murad III.

The Atik Valide Mosque is a large, impressive building with a central dome, four smaller domes, and four minarets (tall, thin towers). The mosque's exterior is adorned with intricate carvings and decorations, including calligraphy, geometric patterns, and glazed tiles. 

The mosque's interior is equally impressive, with a large central prayer hall and a series of smaller prayer rooms. The walls and ceiling of the mosque are adorned with beautiful frescoes and calligraphy.

The Atik Valide Mosque is an active place of worship open to the public. It is an important site for the city's Muslim population and is a popular destination for tourists and pilgrims. The mosque is a beautiful and historic site and is a must-see destination for anyone interested in the history and culture of Istanbul.