Even if you’ve climbed every route around Santa Fe, banked every turn on the trails at La Tierra and know the entire crew at Sangre de Cristo Mountain Works by their nicknames, you may not have heard of Buckman Cave. It doesn’t show up on most maps, and the locals who know it best keep it hush-hush to avoid attracting riff raff and inexperienced cavers. Unless you’re friends with the right people, you might not be aware there’s a refrigerated adventure waiting for you in the heat of the summer, a short drive from downtown, as long as you know what you’re doing.

Tucked into the volcanic rock of Caja del Rio Canyon, better known locally as Diablo Canyon, the cave at first looks like an unremarkable slot. Soon after you enter, the walls close in, the ceiling falls and it seems as if you've reached the end. Slither through a gap on the back wall near the floor and the ceiling lifts up to another chamber—which leads to other tunnels, which snake toward more rooms, deep underground. The air is cool, almost cold. A few small bats cling to the ceiling in places. Flick off your headlamp and you could be at the center of the earth. Now is a great time to treat your buddy with a surprise flash photo.

Despite sounding like a quaint way to spend a hot summer afternoon, Buckman Cave is no place for casual spelunkers. It's dangerous, and not in a simple "watch your head" kind of way. Immediately inside the entrance is a doorway to a room that's eerily dark. The reason is simple: It lacks a floor.

The bottom of the darkness is 80 feet straight down. In the early 1980s, Adam Blum, a young Santa Fe man, slipped and fell to his death here while having a look around. In 2003, Lawrence Cassell came to explore the cave and brought along his four-month-old pit bull puppy. The dog quickly fell off the same cliff. It survived, with a broken leg and lacerated tongue, but it took rescuers a full day to get the pooch out of the pit.

Elsewhere in the cave, there is a slippery section sloping over a 15-foot-drop that's best navigated with a rope. There are also loose rocks, disorienting turns through multiple chambers and a vertical shaft so tight it can act like a Chinese handcuff—dropping through it is easy, coming back up is is only so if you're on Atkins.

This year marks SFR's 40th anniversary. Celebrate with us by reading excerpts of stories that have graced our pages through the years. This year's Summer Guide content begins here.