Ephesus or Efes, was an ancient Greek city on the coast of Ionia southwest of Selçuk in İzmir Province, Turkey. It was built in the 10th century BC on the site of the former Arzawan capital by Attic and Ionian Greek colonists. During the Classical Greek era it was one of the twelve cities of the Ionian League. The city flourished after it came under the control of the Roman Republic in 129 BC. The city was famed for the nearby Temple of Artemis, one of the Seven Wonders of the Ancient World. Among many other monumental buildings are the Library of Celsus, and a theatre capable of holding 25,000 spectators. In early Christian times, the city was home to a significant Christian church, mentioned as one of the seven Churches of the Book of Revelation. Ephesus was inscribed as a UNESCO World Heritage Site in 2015.