If you decide to visit Ephesus while you are staying in Kusadasi, you will also have the chance to see one of the Seven Wonders of the Ancient World, the Temple of Artemis, or what is left of it.
A few pieces of marble and a single column comprising the temple's ruins are only about 5 minutes drive from the Bottom Gate of Ephesus which is around 12 miles north of Kusadasi.
From there, you can see Ayasuluk on which Isa Bey Mosque and the Church of St. John stand and, in the distance behind them, the Byzantine castle.

The Artemis of Ephesus, sometimes called Diana, is not the same figure as the Artemis worshiped in Greece. The Greek Artemis is the goddess of the hunt. The Ephesus Artemis was a goddess of fertility and was often pictured as draped with eggs, or multiple breasts, symbols of fertility, from her waist to her shoulders. The goddess bears many features of Anatolian mother goddess Cybele, wearing a mural crown in shape of temple indicating that she is the protector of cities. A crescent on her forehead indicates that she is the moon goddess and she also bore the symbol of the bee, the emblem of Ephesus, which indicates that she is a unique product of Anatolian mythology.

The earliest traces of the Artemision go back to the 8th century B.C. During the first half of the 6th century B.C. it was constructed of marble, 115 meters long, 55 meters wide and 18 meters high and contained a total of 127 columns, 36 facade columns being decorated with reliefs. The temple was destroyed in 356 B.C. by Herostratus, a young Ephesian who burnt it to the ground because he wanted to be mentioned in history.
The Ephesian authorities not only executed Herostratus, but, to prevent him from achieving his goal, they also forbid mention of his name under the penalty of death. Obviously, their attempt failed as the ancient historian Theopompus recorded the event and Herostratus in his history and his motivation - fame at any cost, gave us the term herostratic fame.

After that, the Ephesians decided to build a larger and more magnificent temple in place of the old one. In 334 B.C. Alexander the Great passed through Ephesus and learning that the temple had been destroyed and burnt down on his birthday, he offered financial help but asked for the new temple to be dedicated to him. However, the story says that the proud Ephesians refused the offer but didn't want to offend him so they told him: "How can a god help another god?"

Although the temple was rebuilt, it was again destroyed during the invasion of the Goths in 263 A.D. It lost its importance with the spread of Christianity and its remains were used as building material for many buildings for centuries.
Many archaeological pieces from the site were sent to the British Museum and a few to the Istanbul Archaeological Museum during the excavations in 19th and at the beginning of the 20th century.