The ancient Romans were religious and built temples to honor the gods. Not all of the temples have survived in mint condition, and the ones that have, remain as ruins, but at least tourists can still go and see the former glory of the Roman Empire.
The Temple of Divus Romulus was built by Emperor Maxentius to honor his dead son Valerius Romulus. Romulus was deified as a god and the temple was meant to honor his death. The original temple has changed quite a bit. Pope Felix IV changed some of its features to make it look more modern, but parts of the original building still stand.
The Temple of Castor and Pollux was built to give thanks to the twins gods Castor and Pollux. The consul Aulus Postumius Albinus built the temple when the Roman army defeated the army of King Lucius Tarquinius Superbus. Now, only bits of the columns remain, but at one point it was the gathering place of the Senate.
Temple of Venus and Rome was the largest recorded temple in ancient Rome. The Temple was built by Emperor Hadrian and finished under Antoninus Pius. The temple was dedicated to the goddess Venus Felix (goddess of good fortune) and to the goddess Roma Aeterna (eternal Rome). The Temple was damaged several times by fire and earthquake, but it’s still a functional building.