Medical Definition of dorsiflexion. : flexion in a dorsal direction; especially : flexion of the foot in an upward directionâcompare plantar flexion.
Willis Tower. The Willis Tower, built as and still commonly referred to as Sears Tower, is a 108-story, 1,450-foot (442.1 m) skyscraper in Chicago, Illinois, United States.
2013: One World Trade Center towers over lower Manhattan in New York City. The building was deemed the tallest building in North America, snatching the title previously held by Willis Tower in Chicago (previously titled Sears Tower).