Nature
Cage the Elephant sings that there ain't no rest for the wicked, but while 12 Monkeys certainly features elephants in cages, it disagrees with the no rest part.
The film suggests there is a place where people can receive respite and restoration, but it's not a spa you'll find in any city. Instead, the film believes that nature is the place to go when you feel like having a me day.
The commercials for Key West clue us into this. These advertisements appear several times throughout the film and always feature a come-hither suggestion to enjoy the ocean scenery, which is shown to be quite fetching. The Keys promise a better, less stressful life:
Are you at the end of your rope? Are you dying to get away? The Florida Keys are waiting for you.
Yeah, beaches do sound more peaceful than mental hospitals, city streets, and apocalyptic nightmares. In fact, Railly and Cole plan to travel to the Keys and wait for the end of the world. Had they managed to catch their flight, we imagine the film would have had a very different ending.
Perhaps the most telling example of nature's healing properties is the scene where Railly and Cole travel to the woods for some impromptu surgery. The sun is shining, Cole's loving the fresh air, and Railly is busy digging a bullet out of his leg.
It may not sound like a restful hike (because it isn't) but it is one of the few scenes to feature Cole healing. Most of the others show the guy getting beat down, physically and mentally.
In another scene, Cole heals in a future hospital, but in the year 2035, nature is permanently off-limits to people. Instead, the Scientists hang a giant painting over his bed. The painting is "Valley of the Yosemite" by Albert Bierstadt and features a sunset over Yosemite Valley (Albert Bierstadt, by the by, was famous for his landscapes).
Unfortunately, there's not enough nature to go around in 12 Monkeys, so its curative properties remain largely untapped by its stressed-out, mentally damaged, and ill-fated characters.
Huh, does anybody else feel like going on a hike?