Lake Züri 100

A 106-kilometer circumnavigation of Lake Zürich on forest trails, hilltop paths, and singletrack — with no course markings anywhere on route. All navigation is done exclusively via GPX track on a watch or phone. Starting and finishing at Albisgüetli in Zürich, the loop traces the ridgelines and valleys on both sides of the lake: climbing south through the Albis chain, descending to Rapperswil-Jona at the midpoint, then ascending the Pfannenstiel ridge on the return leg. With an 18-hour cutoff, most runners cover the final stretch in darkness. A mandatory cold-weather gear kit is required, reflecting the unpredictable conditions of a late-March Swiss start.