monosomething else. it's costing you billions, yes billions. here's griff jenkins with congressman mica. >> reporter: with nearly 900,000 properties and 3 billion square feet, many properties are under-utilized, mismanaged or sitting empty, costing the taxpayers billions of dollars. we are just blocks from the u.s. capitol, where this building, opened by the gsa has been sitting empty over five years. congressman john mica of the transportation and infrastructure committee wants something done about it. >> congressman, where are we? >> well, we near an empty federal building that has been vacant for five years, costing the taxpayer a lot of money. as you can see, there is nobody here. >> reporter: and in this particular building, you said, it has been empty five years, whose building is it?