The Basilica of St. Jean is a significant Christian landmark located in Selçuk, a small town near Izmir. According to Christian tradition, St. Jean (St. John) lived in the area with the Virgin Mary and wrote the Book of Revelation in a cave nearby. The basilica was built in the 6th century AD by the Byzantine Emperor Justinian I on the site where St. Jean was believed to be buried. It became a major pilgrimage site for Christians and was one of the Seven Churches of Asia mentioned in the Book of Revelation.

The basilica consists of a main prayer hall with an apse at the east end, a baptistery, and a courtyard. The prayer hall is decorated with beautiful mosaics and frescoes, some of which date back to the 6th century. The most prominent feature of the basilica is the Tomb of St. Jean, which is located under the apse. The tomb is a small chamber made of marble with a stone sarcophagus in the center. It is surrounded by a wrought-iron fence and covered by a domed roof.

In the courtyard of the basilica, there are several columns and capitals from the original church, as well as a marble fountain. The baptistery, which is located on the north side of the prayer hall, is a small octagonal building with a dome. It was used for the baptism of new converts to Christianity.

Today, the Basilica of St. Jean is a popular tourist attraction and a site of pilgrimage for Christians. It is also part of the UNESCO World Heritage Site that includes the nearby ruins of the ancient city of Ephesus. Visitors can explore the basilica and see the Tomb of St. Jean, as well as the beautiful mosaics and frescoes inside. There is also a small museum on the site that displays artifacts from the basilica and the surrounding area.

In summary, the Basilica of St. Jean is a historically significant and beautiful Christian landmark that attracts visitors from around the world. Its rich history, beautiful artwork, and connection to St. Jean make it a must-see destination in Izmir.