Take the free park shuttle to the Temple of Sinewava, walk one mile to the end of the paved walkway, and begin hiking up the river. Two hours upstream, at the intersection with Orderville Canyon, hikers will encounter the narrowest and most spectacular section of the Zion Narrows.
Photograph by Mike Segar, Reuters Second City is back in second place, at least when it comes to height. New York's One World Trade Center will officially open next year as America's tallest building, topping Chicago's Willis Tower by 325 feet (99 meters). The distinction hinges on a definition. According to the Council on Tall Buildings and Urban Habitat, the needle atop the new trade center is a spire, not an antenna.
Chicago imposed a height limit of 40 meters in 1893, but New York raced ahead with large and tall blocks. Many of these, such as the Singer, Woolworth, MetLife and Chrysler buildings, tapered off with campanile towers, battling to be tallest in the world. The first skyscraper to break the half-kilometer mark, the world's tallest building between March 2004 and March 2010 is also one of the greenest -- certified LEED platinum in 2011.