CHERNOBYL, Ukraine — On contaminated land that is too dangerous for human life, the world’s wildest horses roam free. Across the Chernobyl exclusion zone, Przewalski’s horses graze in a radioactive landscape larger than Luxembourg. …Four decades on, Chernobyl remains too dangerous for humans. But the wildlife has moved back in. Wolves now prowl the vast no-man’s-land spanning Ukraine and Belarus, and brown bears have returned after more than a century. Populations of lynx, moose, red deer and even free-roaming packs of dogs have rebounded. …With human pressure gone, parts of the exclusion zone now resemble European landscapes from centuries past, he said, adding: “Nature recovers relatively quickly and effectively.” Trees pierce abandoned buildings, roads dissolve into forest, and weathered Soviet-era signs stand beside leaning wooden crosses in overgrown cemeteries. …“Most forest fires are caused by downed drones,” said Oleksandr Polischuk, who leads a firefighting unit in the zone.