Ephesus was a Greek city first, then a Roman one. At its peak around 2,000 years ago, around 250,000 people lived here - making it one of the largest cities of its time. Big ships sailed right up to its harbour, full of grain, olive oil, cloth and pottery.
The most famous building still standing is the Library of Celsus. Its two-storey stone front, covered in carved statues and columns, has been put back together piece by piece. It used to hold around 12,000 hand-written scrolls. That was an enormous library for its day.
There is also a huge open-air theatre carved into a hillside. It could seat around 25,000 people - more than a Premier League football stadium - all looking down at a stage where actors performed plays, music and speeches with no microphones at all. The shape of the stone seats bounced the sound around so even the back row could hear.
Walking down the main street of Ephesus today, you can see the deep ruts that chariot wheels wore into the stones, the marble counters of old shops, the public fountains, and even an old toilet with neat rows of seats side by side. It is one of the best places in the world to imagine what daily life was like 2,000 years ago.