When you get off the Pyramide Metro station, the very first thing you see upon exiting is the old city gate in the walls of Rome. Pan left and the very next thing is the Pyramid of Cestius. Caius Cestius was a wealthy Roman citizen who, inspired by the pyramids of Egypt, decided he wanted a white marble pyramid as his funerary monument. He had his tomb built into the city walls. His goal of not being forgotten certainly succeeded as we still know who he was today, some two thousand years after his passing.
His monument backs onto the “English” Cemetery, known technically as the Cimiterio Accatolico (non-Catholic cemetery), final resting place of many English expatriates (and Russian, and American, and French…) including the luminaries of 19th century Romantic literature, Shelley and Keats. The Pyramid of Cestius is in fact open for tours, but they only offer them one day a week, twice a month, and you need to make reservations.