I'm getting ready to teach a month-long course in Mexico with my friend Charles Heath. During the planning process, I've been thinking a lot about the Maya exodus from cities like Palenque and Calakmul at the end of the classic period around 800 C.E. By the time the Spanish arrived in Mexico in 1519, most major Mayan cities had been abandoned for close to 700 years (give or take a few decades). That's roughly the same amount of time that separate us from the world of Christopher Columbus and Hernan Cortes.
Nature can take back a lot in 700 years. Whole cities can be engulfed by forests and rivers. In fact, the 30th anniversary of the Chernobyl nuclear disaster got me thinking about cities in the former Soviet Union that had been abandoned. An internet search produced this amazing video of Pripyat, a Ukrainian city of 50,000 residents that was abandoned on April 27, 1986 after Chernobyl. The film was shot from a drone because the city was so contaminated that the government deemed it uninhabitable for the next 20,000 years. Despite the toxic threat posed by the radioactive contamination at the site, the forest is already claiming the ruins of the city.