Ephesus was an Ionian Greek city in ancient Anatolia, founded by colonists from Athens in the 10th century BC. The city was located in Ionia, where the Cayster River (Kucukk Menderes) flows into the Aegean Sea, and was part of the Panionian League.

Today's archaeological site lies 3 km south of the Selcuk district of Izmir Province. The ruins of Ephesus are favorite international and local tourist attractions, partly owing to their easy accessibility from Adnan Menderes Airport and via the port of Kusadasi.

Ephesus hosted one of the seven churches of Asia, addressed in the Book of Revelation (2:1–7). It is also the site of a large Gladiator graveyard.

It is a vast site, and despite not yet being fully excavated the ruins that are visible give some idea of the city's original splendour, and the names associated with the ruins are evocative of its former life. The huge theatre dominates the view down Harbour Street which leads to the long silted-up harbour.

The Library of Celsus, whose fasade has been carefully reconstructed from all original pieces, was built ca. AD 125 by Gaius Julius Aquila in memory of his father, and once held nearly 12,000 scrolls. Designed with an exaggerated entrance - so as to enhance its perceived size, speculate many historians - the building faces east so that the reading rooms could make best use of the morning light.