American Gary Arndt is on a mission to see as many UNESCO World Heritage Sites as possible. At almost 300 and counting, he's got a few favorites, reflected in this gallery.
Pontcysyllte Aqueduct (Wales, UK) —
The 18-kilometer-long aqueduct is a feat of engineering and metal architecture. The use of both cast and wrought iron in the aqueduct enabled the construction of arches that are light and strong. "Industrial-themed sites don't get the same amount of attention as the ancient sites do, but they are just as important to the development of the modern world," says Arndt. He snapped this beautiful shot during his visit to the site in 2011.
Nahanni National Park (Northwest Territories, Canada) —
"Nahanni National Park in Canada (is) really amazing," says Arndt. "It was one of the first 12 World Heritage Sites listed back in 1978, yet few people know about it. It's one of the greatest national parks in the world."