The International Space Station (ISS) orbits Earth at an average altitude of about 400 kilometers (about 250 miles) and travels at a speed of approximately 28,000 kilometers per hour (about 17,500 miles per hour).
Known by another name as the Sears Tower until 2009 when the building changed ownership, Willis Tower is the tallest building in America with 103 floors. Step up to the observatory with its transparent glass floor for the chilling feeling of floating in the sky and looking straight down at the street.