The Athabasca Glacier has retreated roughly 1.5 kilometres since 1890, and the interpretive markers along its approach road are dated to prove it. That measurable loss is the quiet subject of every banff to jasper bus tour that runs the length of Highway 93 North. The road itself was not built for scenery. Construction began in 1931 as Depression-era relief work, with crews cutting a gravel track through the Bow and Sunwapta valleys by hand and horse. The route opened in 1940. Wilderness surveyor A.O. Wheeler had earlier called the corridor the Wonder Trail, a name that stuck in guidebooks long after the pavement arrived in the early 1960s. Today the parkway forms part of the Canadian Rocky Mountain Parks UNESCO World Heritage Site, inscribed in 1984. What the corridor protects is the Columbia Icefield, the largest body of ice in the Rocky Mountains south of Alaska. It covers approximately 325 square kilometres and reaches depths near 300 metres. Its meltwater is hydrologically remarkable: from the Snow Dome, water departs toward the Arctic, Pacific and Atlantic oceans, making it one of the few triple continental divides on the planet. The Athabasca Glacier is the icefield's most visible tongue, and the only one that touches the highway. Six outlet glaciers descend from the main body. The geology explains the shape of the drive. Sunwapta Pass rises to 2,035 metres. Bow Summit, at 2,069 metres, is the highest point on any Canadian highway crossed by a public road of this class. Between them lie Peyto Lake, whose rock-flour turquoise comes from glacial silt suspended in the water column, and Bow Lake, fed directly by the Crowfoot and Bow glaciers. Mistaya Canyon, Sunwapta Falls and Athabasca Falls each mark a point where meltwater has cut limestone into narrow slots. Human infrastructure remains deliberately sparse. The Glacier Skywalk, a cantilevered glass-floored platform 280 metres above the Sunwapta Valley, opened in 2014 and won an Institute of Structural Engineers award for its restraint. It is one of the few permanent additions in decades. Access to the corridor requires a valid park pass; the daily rate for one adult is 12.25 CAD. Scheduled coach services along this route have become the default for travellers without a vehicle, and Icefields Parkway coach tours now carry a substantial share of summer visitors between the two townsites. A well-run banff to jasper bus tour tour treats the parkway less as transit than as a sequence of stops, each with its own geological argument.