They once made millionaires. Now they make tourists happy. Take a step back in time at these mines:

Mollie Kathleen Gold Mine, Cripple Creek

The mine’s website recalls the story of Mollie Kathleen, who one day in 1891 “noticed an interesting rock formation that winked back at her.” The history goes: “With her heart racing, Mollie nonchalantly hid gold samples.” Your heart might race as well on the 1,000-foot drop of the underground tour.

Hidee Gold Mine, Central City

The tour enters a tunnel that spans an area once considered “the richest square mile on Earth.” That’s only half of the experience here. You also can test your skill at gold panning. The Hidee has a motto: “Always keep what you find, and you will find something.”

Argo Mill and Tunnel, Idaho Springs

This might be the most recognized attraction of its kind in Colorado — the red infrastructure impossible to miss on the drive along Interstate 70 through Clear Creek County. This was a site of technological ingenuity, responsible for processing an amount of gold ore worth billions in today’s dollars.

Country Boy Mine, Breckenridge

Just as the mine knew many enticing qualities of the late 1800s — gold, silver, lead and zinc — so it boasts many today. Your headlamp lights the way deep into the tunnel. Outside, families have panned for gold, met burros and hunted for treasure along a wooded trail.

Bachelor Syracuse Mine, Ouray

Guides take you on a dark walk spanning 1,500 feet and years of dreaming, toiling and risking it all as miners did in these San Juan Mountains. They provide the scenery from a stream said to still twinkle with those precious metals sought. A cafe is open on weekends to fill you up on pancakes.

Old Hundred Gold Mine, Silverton

In the heart of the San Juans is a tour through the heart of Galena Mountain, which still bears the mineral that three German brothers cherished. The Neigolds were the original owners, known to entertain the camp with song and performances. They’d probably be proud of the entertainment today.