Near the beach is Tarragona's well-preserved amphitheatre, dating from the 2nd century CE, where gladiators hacked away at each other or wild animals. In its arena are the remains of a 6th-century Visigothic church and a 12th-century Romanesque church, both built to commemorate Saint Fructuosus and two deacons, believed to have been burnt alive here in CE 259. At the time of research, parts of the amphitheatre were undergoing restoration, though the upper viewing gallery was open (and admission free).
Much of the amphitheatre was picked to bits, the stone used to build the port and the two churches, so what you see now is a partial reconstruction.