Largo di Torre Argentina is an open archaeological area in central Rome with the remains of four Republican-era temples and part of Pompey's Theatre complex. It is best known as the place where Julius Caesar was assassinated in 44 BC, though the surviving ruins are older and more layered than that single story suggests.
The site sits below modern street level, so even a quick stop gives a clear view across the temple platforms and columns. It is also famous for the cat sanctuary that has long occupied the ruins.