The holiday spirit might not totally explain what makes Rudolph’s nose glow so bright.

Thirty years after a nuclear power plant exploded at Chernobyl, the reindeer that walk the picturesque, snow-capped mountains of Scandinavia are still radioactive.

They weren’t the only ones affected. For generations, the Sami people, native to the Arctic North, lived in harmony with nature. Many worked as boazovázzi, or “reindeer walkers,” herding the animals over hundreds of miles of terrain and selling their meat come slaughter season. The reindeer were a cultural and economic centerpiece for the Sami people.

But the explosion — considered the worst civilian nuclear disaster in history — coated the earth with toxic material, turned the reindeer radioactive, and poisoned the Sami people’s way of life.

Photographer Amos Chapple with Radio Free Europe traveled to the Norwegian village of Snasa, where he met with herders fighting to preserve their traditions.

Chapple shared a few photos with us, and you can read the whole story here.

In the fallout of Chernobyl, streams of radioactive material spewed into the atmosphere above the Soviet Union and across Europe. Among the most dangerous fission products was cesium-137.

^{Graffiti on a wall in Germany reads, “Oh God, it rains.”Frank Rumpenhorst/AO}

^{Source: Radio Free Europe}

The radioactive materials poured into the lakes and forests, contaminating wildlife, berries, and plants. It also got to a spindly green fungus called lichen, a reindeer’s favorite snack.

^{Amos Chapple}

^{Source: University of Texas}

For 9,000 years, the Sami people tied their cultural identity to the reindeer. The animal provided food, income, and traditions they passed on. Chernobyl brought an abrupt end.