"La Farnesina" - we even like the name... as in the "little, cutesy Farnese (family) palace...." And a pleasure palace it was for the Tuscan banker Agostino ("the Magnificent") Chigi who built it (1508-11) and the Cardinal Farnese who then bought it (1534), and for us now.
Standing relatively alone in its grounds, now restored, and housing wonderful frescoes by Raphael and his students, La Farnesina is a delightful place to experience Renaissance Rome. In the fresco of the Three Graces (below), the one with her back to us is attributed to Raphael. Chigi didn't have many years to enjoy his art; he died in 1520, 4 days after Raphael.
It's the locus of great stories too - like the wealthy owners who threw parties with gold and crystal tableware and then when finished with each course, ostentatiously threw them into the Tiber. But the rumor is that they had a net in the Tiber to get back their valuable glasses and forks and who knows what else.
This area of Trastevere holds other treasures as well, and is worthy of a few hours: the Palazzo Corsini across the way that holds part of the State's Renaissance art collection, complete in the grand palace where it was meant to be shown (off), and behind that, the lush Botanical Gardens that climb up the Gianicolo. All these have a relatively low admission charge.
La Farnesina and its sister sites are just a few steps from the crazy heart of Trastevere and just across the Tiber from the center of old Rome, yet they seem a world apart, and hence, make our RST Top 40.
The official website can be converted into English. See, e.g. this site on hours, etc. Generally 9 a.m. - 1 p.m. Monday thru Saturday (except when the Italian President is visiting, as he was one day we tried to enter).