France24.com reports that the largest archeological site and urban center of the Mayan civilization suffered irreparable damage after tourists accessed forbidden stairs to the site.
"Sadly, many tourists climbed Temple II and caused damage," said Osvaldo Gomez, a technical adviser at the site, which is located some 550 kilometers (340 miles) north of Guatemala City.
"We are fine with the celebration, but (the tourists) should be more aware because this is a (UNESCO) World Heritage Site," he told local media.
Gomez did not specify exactly what was done.
Temple II, which is about 38 meters (125 feet) high and faces the central Tikal plaza, is one of the site's best known structures.
Friday marked the end of an era that lasted 5,200 years, according to the Mayan "Long Count" calendar. Some believed the date also marked the end of the world as foretold by Mayan hieroglyphs.
More than 7,000 people visited Tikal on Friday to see native Mayan priests hold a colorful ceremony and light fires as the sun emerged to mark the new era.
Critics complained that the event was really for tourists and had little to do with the Mayans. About 42 percent of Guatemala's 14.3 million residents are native Mayans, and most live in poverty and endure discrimination.
The ancient Mayans reached their peak of power in Central America between the years 250 and 900 AD.
UNESCO declared Tikal a World Heritage Site in 1979