Peru’s Machu Picchu, an iconic tourist attraction drawing visitors from around the world, instituted a new set of rules to conserve the historical site.

The guidelines went into effect July 1, as a result of a study by a U.S. archaeologist and recommendations from UNESCO officials on how to ensure the site doesn’t sustain damage from the increase in tourism.

One of the rules prohibits tourists from spending the entire day at the site. Instead, there are two periods each day allowing travelers to enter the area; one in the morning, 6 a.m.–12 p.m., and one in the afternoon, 12­–5:30 p.m. All visitors must enter with either an official Machu Picchu guide or licensed tourist guide, and each guide will be permitted to take a maximum of 16 people during each entrance into the area.

Officials updated its prohibited list to include bags larger than 16 inches, food, drinks, alcoholic beverages, cigarettes, illegal substances, umbrellas, photographic tripods, selfie sticks, musical instruments, high heels, children’s strollers and more. The site does not allow tourists to climb or lean on walls, touch or remove any items, get naked, make loud noises or feed the wild animals in the protected region.

The goal is not to inhibit the visitor experience, but to protect the historic site. Visitors must respect the new rules or risk being removed from the area.