The Brood X cicadas come every 17 years, and after appearing in D.C. a few weeks ago, are just about all gone, with their offspring living underground until they re-emerge in 2038.

The first sign of the cicadas is seeing their discarded shells. After emerging from the ground, they climb up to find the nearest vertical surface and emerge through the back of their exoskeletons, which remain stuck to the surface.

Living in D.C., one of their next moves is to make sure they see all the usual tourist sights.

They are everywhere. The estimate of the number of cicadas range somewhere between billions and trillions, and they cover the area so densely that they show up on weather radar.

Fortunately, they don’t damage plants except for the tiny twigs of young trees, so after they go back underground for another 17 years, all that remains is to sweep up after them.