Back in the 1800s, when a group of archaeologists set about the difficult task of excavating Pompeii, they ran into a sticky situation. At a time when the subject of sex was taboo among the general public, almost all the objects they unearthed were erotic. As a result, treasure troves of nude sculptures, frescoes of copulation, and gods with impressive private parts were stashed away in secret rooms, rarely revealed. Now, for the first time, 70 of these evocative objects are on view. —Elena Clavarino