This 2.5 mile-long tunnel winds underneath the streets of West Allis and has been a topic of recent conversation in the adventure community. Check it out for yourself to get some more steps on your FitBit and see an even sketchier part of 'Stallis - if that's possible.
Branching off of the Menominee River, Honey Creek is enclosed partially by this underground tunnel. The entrance is marked by a large grate in McCarty Park, then winds underneath neighborhoods before emerging north of I-94. At one point, the tunnel is only 15 feet beneath the State Fair grounds! There are many turns that follow the river's offshoots, but follow the main trail and you'll rack up 2.5 miles.
Park at McCarty park and walk to the grate pictured. Depending on who visited last, you might need to unscrew the bolts connecting the grate to the wall to enter the tunnel.
Have you been to Honey Creek? What did you think? Leave any tips of your own or observations in the comments to help other explorers!