course there's the walmart exceutives one to with there own private airstrip...
wouldnt suprise me if they have undeground tunnels that lead to others...
i mean u can hire companies to do this anyone can really so its not crazy......
Arkansas
CUSHMAN - Caverns west and west-north-west of the town are legendary for stories of deep cavern systems, encounters with hairy humanoids with an attitude, giant serpents and insects, deadly gas pockets, strange
electro-magnetic phenomena and unexplained disappearances. One of these is "Blowing Cave" which lies in the mining area NW of Cushman and is located 1/4 mile north of a road leading west from Cushman, one of
several caverns in the area, some of them possibly connecting at the deeper levels. Between the large entrance and an underground lake far back in the cave is a trail that winds through an area of rubble or "breakdown". The
trail is intersected by a crack in the earth [between the entrance and the lake] that, if followed into the breakdown, widens enough to enter. This chasm is reportedly an entrance to the endless networks of the alien underworld.
source: Charles Marcoux - - George Wight - D. A. Lopez; TRIP TO A CUSHMAN CAVERN
from http://www.burlingtonnews.net/tunnels2.html
theres always more though trust me.... even just the stuff u can easily visit in the public sector is mind blowing...