The Capitol Extension Immediately north of the Capitol is the underground extension which was built in order to provide more space for committee rooms, offices, an auditorium, a public dining room, and the Capitol Bookstore. The extension covers over 600,000 square feet of space and has four levels with the two lower levels being for employee parking. Tunnels connect the extension to other state buildings. The extension has the feeling of being outdoors due to the massive skylights that provide natural light and spectacular views of the Capitol dome. There is also an outdoor rotunda that shows you how deep underground you really are!