Interesting historical ruins with models and exhibitions explaining the situation here.

Andalusia - Cadiz Beautiful archaeological displays showcasing the ancient Roman theater built by Lucius Cornelius Balbo in 43 BC. Less than a third of the original amphitheater survives, with the background and stage scenes completely gone. You can see the original foundations through the glass floor, view the theater model, and watch an interesting film (in Spanish and English) vividly depicting the reconstruction of the Roman era. You can also walk through the tunnel into the open-air theater, all of which is free to enter!