An environmental activist, who was walking across the U.S. barefoot to raise awareness of climate change, was struck and killed by a SUV on a Florida highway.

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It happened Saturday afternoon as Mark Baumer, 33 of Rhode Island, was walking on the shoulder of U.S. 90 in Walton County, according to the Florida Highway Patrol, which also confirmed Baumer died at the scene.

The 51-year-old driver, who is facing charges in the case, swerved out of her lane and onto the shoulder, where she hit Baumer, authorities said. He died at the scene.

Baumer had just finished his 100th day on the road and had posted an eerie photo with just his toes showing on the road with the word "killed" spelled out in yellow paint on his equally eerily named blog, notgoingtomakeit.com, before he was struck and killed.

On another Baumer website, Barefoot Across America, the activist explained why he was walking across the country. He wrote he wanted “to save the earth” and called climate change “the greatest threat” the world has ever faced.

Baumer completed another cross-country walk back in 2010, but with shoes on.