The Acropolis represents the highest point of the city, on a rocky hill, with a panoramic view of all a big part of Fthiotida. The castle includes the preserved Medieval fortification that surrounds the acropolis and it was initially built around the 5th century BC.
Inside the walls of the castle, is situated the archaeological museum of Lamia. It is housed in a very impressive building that used to host the army of the city when Otto was the King of Greece.
The exhibitions of the museum depict the historical evolution of the broader region. While the artifacts cover a period from the Prehistoric Era to the Roman Times. The exhibits are findings from excavations of the local region.