AP
US President Barack Obama arrives at the Iowa State Fair, August 13, 2012, in Des Moines, during a three-day campaign bus tour of the state.
The president has no shortage of transit options, from Air Force One and Marine One to Cadillac One. Now meet Ground Force One, the president's armored bus and the most recent edition to the presidential fleet.
We've compiled some of Ground Force One's most impressive features: