Photos: Road Trip 'pictures of the day' collection

On July 8, a little more than two weeks into Road Trip 2009, CNET News reporter Daniel Terdiman posted this picture, challenging readers to identify what the yellow ball is. His thought was that this might be a fun, interactive, task that could get people involved.
I didn't really intend to make it a daily Road Trip feature, but the response to the contest was huge--and stayed huge for the next three weeks as, each day, I posted a new photo and a new challenge.
Of the 23 daily challenges, this one generated the most interesting responses--from nuclear radiation measuring equipment (the photo was taken in Arco, Idaho, the first town in America to ever be powered by nuclear energy), to a recycling bin, to a Cloudbuster, to a portable nuclear/electric power-generating device for military use in remote areas. No one seemed entirely sure what the answer was.
The truth was, I didn't either. (In subsequent days, I always knew what the picture was). But it turns out the yellow ball--and the other one just like it down the same block in Arco--is a former marker strung along power lines so that pilots can see the lines. A little less interesting than a portable nuclear energy-generating device, but there you have it.
Thanks to everyone who participated. And stay tuned for the Road Trip 2010 picture of the day challenge next summer.
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The Road Trip picture of the day challenge for July 10, this is artist Nancy Holt's terrific Earthwork, the Sun Tunnels, near Lucin, Utah.
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The Road Trip picture of the day challenge for July 11, this is Newspaper Rock, a stunning petroglyph near the entrance to Canyonlands National Park in Utah.
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The Road Trip picture of the day challenge for July 13--I missed a day on July 12--this is one of the late artist Starr Kempf's incredible kinetic sculptures, as seen on display in front of his family's Colorado Springs, Colo., house.
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The Road Trip picture of the day challenge for July 14, these are giant springs designed to protect the buildings inside the Cheyenne Mountain Complex, outside of Colorado Springs, Colo.
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The Road Trip picture of the day challenge for July 15, this was just one of the many painted horses that were part of Odgen, Utah's Pioneer Days celebration.
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The Road Trip picture of the day challenge for July 16, this is Dewey Bridge, along Utah's scenic Route 128, near Moab, Utah.
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The Road Trip picture of the day challenge for July 17, this is the Lexington Stamp Mill, in Butte, Mont.
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The Road Trip picture of the day challenge for July 18, this is Earthquake Lake, or Quake Lake, near West Yellowstone, Mont.
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The Road Trip picture of the day challenge for July 19, this is the gondola that takes visitors to the Jackson Hole Mountain Resort in Wyoming to the top of Rendezvous Mountain.
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The Road Trip picture of the day challenge for July 20, this is Crowheart Butte, near the town of Crowheart, Wyo.
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The Road Trip picture of the day challenge for July 21, this is a game between the Rookie League (Minor League baseball) Casper Ghosts and Helena Brewers, in Casper, Wyo.
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The Road Trip picture of the day challenge for July 22, this is the Meyer-Womble Observatory, on Colorado's Mt. Evans.
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The Road Trip picture of the day challenge for July 23, this is a waterfall in Idaho Falls, Idaho.
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The Road Trip picture of the day challenge for July 24, this is the "Mexican Hat," near Mexican Hat, Utah.
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The Road Trip picture of the day challenge for July 25, this is the Sheikh Zayed bin Sultan Al Nahyan Falconry Heritage Wing at the Archives of Falconry at the World Center for Birds of Prey, in Boise, Idaho.
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The Road Trip picture of the day challenge for July 26, this is Independence Rock, in central Wyoming.
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The Road Trip picture of the day challenge for July 27, this is a painted bison in West Yellowstone, Mont.
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The Road Trip picture of the day challenge for July 28, this is Landscape Arch, in Arches National Park, near Moab, Utah.
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The Road Trip picture of the day challenge for July 29, this is the Montana state capitol building, in Helena, Mont.
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The Road Trip picture of the day challenge for July 30, this is Wind River Canyon in central Wyoming. More people got this one wrong than any other--except perhaps the yellow balls. Many people thought it was the Royal Gorge in Colorado.
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The Road Trip picture of the day challenge for July 31, and the last challenge of Road Trip 2009, this is Union Pacific Railroad train No. 119. In 1869, it met up with the Central Pacific Railroad's Jupiter, at Promontory, Utah, forming the Transcontinental Railroad. The site is now celebrated at the Golden Spike National Historic Site.
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