New York's Metropolitan Museum of Art is big on bubbles. They inspired Argentinian artist Tomas Saraceno to create a work that rises from the roof of the museum. Titled "Cloud City," the 16 stainless steel-framed bubbles are reachable via transparent staircases. Visitors get spectacular views of the Manhattan skyline and Central Park. The 38-year-old artist says his work reflects the city. So when the sky is blue, you see blue. And when it's cloudy, visitors feel like they're in a cloud.