On August 24, 79 A.D., Southern Italy’s now-notorious volcano, Vesuvius, blew its top. The mountain sent a mushroom cloud of gas and volcanic debris 19 miles into the sky, demolished nearby towns with a 900-degree burst of hot air, and encased the area in ash as deep as 20 feet. Over the years, the equivalent of a time capsule has been uncovered. In a maze of once-grand cobbled streets, stone structures suggest a remarkably comfortable standard of living. Stroll through markets and colonnades, an amphitheater that once hosted gladiators, and public baths with complex furnaces. Marvel at realistic frescoes adorning the walls of opulent villas—plus a slew of less wholesome depictions in bordellos. In the late afternoon, when the sun casts an atmospheric glow, it’s eerily easy to imagine what life must have been like 20 centuries ago.