There are a ton of tunnels in Reston for the pathway system. The most famous is the tunnel by South Lakes High school where people use to skip school and smoke pot.
There is also the WO&D tunnel under the Reston Parkway by the Reston Town Center.
Of course the most famous tunnel in Fairfax county is the Bunny Man bridge tunnel under the railroad tracks near clifton.
There's also a cool tunnel in Lake Anne by the Lake Plaza. Walk all the way to the end of the plaza by the middle of the Lake and make a right on to the pathway. Follow that path around under North Shore drive. You'll pass the Lake Bridge.
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