Climbers started the movement. Forced indoors by weather or circumstances, they built an indoor wall and on it put a bunch of little bumps, some no more than a crack.

They practiced climbing techniques, strengthened fingertips and toes, and talked of climbing mountains and cliffs when the weather broke.

Then, for the very reasons climbers moved indoors, others followed. Today, indoor climbing walls are everywhere, and people of all ages and abilities are reaching for the edges, stepping on the incuts and showing daring by grabbing for the extreme holds.

All this, of course, indoors in air-conditioned comfort and under supervised safety procedures.

And, while indoor climbing still attracts the elite climbers, those reaching for the handholds now are climbers at every level of ability and age. And, in particular, the sport is attracting families.

According to Matt Nielson, manager of Utah's newest climbing gym, Momentum, "Parents are bringing their kids in and the entire family is climbing. I'm also seeing more women who actually want to climb rather than being here just to hang out with their boyfriends."

The story goes that indoor climbing on artificial structures started in England in 1964. People first climbed on rocks embedded in a wall.

The first indoor climbing gym in the United States surfaced around 1987 in Seattle. Climbers, hoping to keep their skills fresh on rainy, snowy days, fixed hand and foot holds on a wall and practiced climbing.

The first climbing center in Utah was also started by climbers and was designed more for bouldering or free climbing than for toprope climbing.

Momentum is not only the newest climbing gym in Utah but also the largest — 20,000 square feet of climbing space, ranging from boulder fields to a 42-foot climbing wall. There are thousands of handholds of various sizes, shapes and purposes, and walls that offer climbers everything from beginning to expert routes.

There are also 13 cracks that are part of the climbing walls for those who are into climbing cracks. These routes are modeled after the cracks in the popular Indian Creek Canyon climbing area near Moab.

Bouldering, as the name suggests, involves free climbing large boulders, which in the case of the Momentum boulders, are man-made.

Bouldering is a branch of rock climbing that is rapidly growing.

Nielson said one reason is bouldering doesn't require a climbing partner — "Although it's more fun climbing with a partner." It can be done with very limited equipment, mainly a pair of climbing shoes and a chalk bag.