You start up a desert trail into rugged Pima Canyon north of Tucson - expecting to see tall saguaros or perhaps a herd of javelina.
Well, surprise! The first thing you come to is an underpass.
The trail leads through a cavernous, concrete tunnel-like underpass beneath a road bridge - similar to what you might encounter while driving a highway. Never mind that you're trekking on a national forest trail.
Odd as it might appear to hikers coming upon it for the first time, the underpass serves an important purpose: providing safety.
A road leading to a subdivision crosses the trail site, and developers installed a bridge and underpass so hikers could avoid the road, said Steve Anderson of the Pima County Natural Resources, Parks and Recreation Department.
The trailhead, at the east end of Magee Road, and the first short stretch of the trail are on county land.
The bridge and underpass "allow the walkers to hike the path without stopping, and the residents to access the northern portion of their subdivision without having to stop and let someone pass," Anderson said.
"It also keeps the subdivision private," he said. "The hikers can't access the subdivision."
Even though this underpass is on a hiking trail, it shares a characteristic with ones that run under city streets and highways: lots of graffiti.
Names, designs, proclamations of love and other scrawls cover the curved ceiling.
Contact reporter Doug Kreutz at firstname.lastname@example.org or at 573-4192.