Glenwood Canyon in the context of Colorado River (U.S.)

Interstate 70 (I-70) is a transcontinental Interstate Highway in the United States, stretching from Cove Fort, Utah, to Baltimore, Maryland. In Colorado, the highway traverses an east–west route across the center of the state. In western Colorado, the highway connects the metropolitan areas of Grand Junction and Denver via a route through the Rocky Mountains. In eastern Colorado, the highway crosses the Great Plains, connecting Denver with metropolitan areas in Kansas and Missouri. Bicycles and other non-motorized vehicles, normally prohibited on Interstate Highways, are allowed on those stretches of I-70 in the Rockies where no other through route exists.

The United States Department of Transportation (USDOT) lists the construction of I-70 among the engineering marvels undertaken in the Interstate Highway System and cites four major accomplishments: the section through the Dakota Hogback, Eisenhower Tunnel, Vail Pass, and Glenwood Canyon. The Eisenhower Tunnel, with a maximum elevation of 11,158 feet (3,401 m) and length of 1.7 miles (2.7 km), is the longest mountain tunnel and highest point along the Interstate Highway System. The portion through Glenwood Canyon was completed on October 14, 1992. This was one of the final pieces of the Interstate Highway System to open to traffic and is one of the most expensive rural highways per mile built in the country. The Colorado Department of Transportation (CDOT) earned the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers for the completion of I-70 through the canyon.

Mixed climbing is an ice climbing discipline used on climbing routes that do not have enough ice to be regular ice climbs, but are also not dry enough to be regular rock climbs. To ascend the route, the mixed-climber uses normal ice-climbing equipment throughout (e.g. double ice tools or ice axes in their hands, and crampons on their feet), but to protect the route, they use both ice and rock equipment. Mixed climbing varies from routes with sections of thick layers of ice interspersed with sections of bare rock, to routes that are mostly rock but which are "iced-up" in a thin layer of ice and/or snow.

While alpinists have used mixed climbing techniques for decades on alpine routes (most north-facing alpine routes are iced or snow-covered), mixed climbing as a standalone sport came to wider prominence with Jeff Lowe's ascent of the partially bolted Octopussy (WI6, M8 R) in 1994. Mixed climbing also led to the sport of dry-tooling, which is mixed climbing on routes that are completely free of all ice or snow. The equipment used — the lengths of ice tools and the use of heel spurs and ice axe leashes — has become more regulated to avoid concerns of being more like aid climbing than free climbing.