Short answers, pulled from the story.
Humans began inhabiting the area surrounding Ephesus by the Neolithic Age, about 6000 BC. Excavations at the nearby höyük of Arvalya and Cukurici have revealed evidence of these early settlements.
The Temple of Artemis was completed around 550 BC and designated one of the Seven Wonders of the Ancient World. Pliny stated the magnificent structure took 120 years to build with over 100 marble pillars each standing 56 feet high.
The river Cayster silted up the old harbor causing resulting marshes that brought malaria and many deaths among inhabitants. Loss of harbor caused Ephesus to lose access to Aegean Sea important for trade.
John is said to have died of natural causes at Ephesus sometime after AD 98 during Trajan's reign becoming the only apostle who did not die as a martyr. His tomb lies thought to be located in the former Basilica of St. John at Selçuk.
May 2018 allowed Austrian archeologists resume excavations after pause. The city ruins were designated UNESCO World Heritage Site in 2015 accessible from Adnan Menderes Airport and resort town Kuşadası.