Question

How was Roman religion similar to Greek mythology? What was the most famous Roman temple?

Answer 1

Roman mythology was very similar to Greek mythology. The majority of the myths were more or less identical, with the exception of name changes and the addition of a few minor gods. The gods kept their "jobs" from Greek to Roman mythology, with Jupiter (Zeus' Roman counterpart) still king of the gods and the god of lightning/thunder, Juno (Hera) was his wife and queen and ruled over marriage and families, exc.

(Here is a simple list of Greek and Roman gods: http://www.dummies.com/how-to/content/gods-and-goddesses-of-greek-and-roman-mythology.html. And more extensive lists can be found here: http://www.pantheon.org/miscellaneous/roman_vs_greek.html
and here:
https://www.oneonta.edu/faculty/farberas/arth/ARTH209/gods_greek_roman.html)

As for the temple, the Pantheon would be very well-known. It stands in the Roman Forum, along with many other temples and other ruins. You can read more about the Forum Romanum here: https://www.khanacademy.org/humanities/ancient-art-civilizations/roman/beginners-guide-rome/a/forum-romanum-the-roman-forum