Its name derives from the Temple of Hephaestus, also known as Τhiseio, as it was, in earlier times, considered a temple of Theseus. The area also takes in the ancient Agora, Petgralona, and Kerameikos, which includes the Assomaton Square.
The area encompasses an ever-increasing variety of popular cafes and meeting points, which are most crowded during summer, and is also served bythe nearby ISAP station of the same name.