Paestum
Paestum is the classical Roman name for the old Greek settlement Poseidonia. In a large area there are three well kept temples, the remains of various houses and a very well documented museum. The impressive temples are on the World Heritage List. Paestum can be reached in one hour by train from Sapri.
www.paestumsites.it/en
Pompeii
Pompeii can also be easily reached by train from Sapri (in two hours) This site also lies close to the railway station.(Pompeii-Scavi)
http://www.pompeiisites.org
http://www.pompeionline.net/pompei-scavi/orari-e-informazioni-biglietteria
Velia
At Velia are the remains of another ancient Greek settlement.