A “stop” sign protects plants and wildlife on Espanola Island in the Galapagos.
Police, seen through the windshield of a truck, stop visitors speeding in Chile’s Atacama desert.
A recently installed cattle guard in a pasture near Valparaiso, Nebraska.
A cattle guard being installed at a pasture near Valparaiso, Nebraska.
A woman stops for lunch while climbing to the top of Mount Reed on Adak Island, Alaska.