You're looking for a bison tube in a Douglas County Open Space
area. Please enter and exit using the trail from either the east or
west trailhead (waypoints below), and stay on the trail except as
needed to locate the cache.
This is a log-only cache. Please bring a pen. There's an
unactivated microcoin for the First-To-Find.
When I first saw this site with its truly bizarre culvert, I was
immediately reminded of H.G. Wells' The Time
Machine, and particularly the 1960 movie
made from that novella. Portals a bit like this culvert were the
entrances to the underground domain of the evil Morlocks. The movie
made it clear that that was not a good place to be.
I don't know for sure that there are Morlocks hiding down there,
but if you hear any sirens, you might want to try to be someplace
else. 
And if this place still doesn't scare you, I have a movie to
recommend. 
Congratulations to
BurgessBunch for the First-To-Find (21 minutes after the cache
was published ).
Additional Waypoints
ET1V5HM - East Trailhead
N 39° 27.051 W 104° 44.069
Park on street nearby and enter at this trailhead (distance to cache 0.1 mi.)
SP1V5HM - West Parking Lot
N 39° 26.993 W 104° 44.347
Parking lot for approach from west, distance to cache 0.14 mi.
WT1V5HM - West Trailhead
N 39° 27.034 W 104° 44.270
West trailhead (park in West Parking Lot, enter park on opposite side of street and proceed to this trailhead)
Morlocks' Maw
| Difficulty: 
| Terrain: 
6 
3