Greenpeace apologized to Peru today for placing a gigantic banner promoting renewable energy on the site of the Nazca Lines, an ancient heritage site, reports the BBC. The damage caused by the environmental group's actions will be long-lasting, officials say, so the country is now planning to file criminal charges against the activists.

Normally, tourists only get to the see the site from the comfort of a plane. Even top officials and presidents are forbidden from treading on the sensitive ground. And on the rare occasions where Peru has allowed officials to visit the site on foot, they were forced to wear special footwear.

Rodrigo Abd / AP

These restrictions didn't stop Greenpeace activists from visiting the site. And not only did they visit, they placed an ad. They put down a banner that read "Time for Change! The Future is Renewable. Greenpeace." Though the future might be renewable, the 1,500-year-old hummingbird carved next to the banner isn't.

According to Greenpeace's apology, the banner was supposed to send a message to UN climate talk delegates meeting in Lima this month. But "rather than relay an urgent message of hope and possibility to the leaders gathering at the Lima UN climate talks," Greenpeace said, "we came across as careless and crass."

The group doesn't just come off as crass. By writing a message in English on a site belonging to a country that has three official languages that aren't English, the environmental group also managed to come across as thoughtless and ignorant. The message wasn't meant for the people of Peru, and yet the group still choose to desecrate an ancient monument to transmit it.

Now that the damage is done, Greenpeace said that it will refrain from using photos of activists laying down the banner in its campaigns. The activist group will also send its executive director Kumi Naidoo to Lima to apologize to the Peruvian government in person.