A pantheon was a place where all the gods (pan-theos) were worshiped; several cities in classical antiquity had one, including Rome, where Marcus Agrippa built one during the reign of Emperor Augustus (27 B.C.-14. A.D.); it was destroyed, then rebuilt by Hadrian about 125 A.D., keeping the dedication Agrippa had made. That building is still standing, and since 609 has been a church, the Basilica of St. Mary and the Martyrs. Authority passed from the popes to the kings of Italy, and after the abolition of the monarchy in 1946, to the Italian government – but Mass is still said there on Sundays and holy days; the building’s longevity is due to its being continuously in use. It’s considered the most popular cultural attraction in the city with 60,000 visitors a year. Now the govrnment and the Church have agreed to charge a 5-euro entry fee, with 70% of the proceeds going to the Ministry of Culture and 30% to the Church. Behind Hadrian’s portico, the basilica is a cylinder with the world’s largest unreinforced concrete dome; the contents are spectacular. (Alessando Tarantino/AP)