Trace is a memorial environmental sound installation that is site-specific to the network of hiking trails near the Burgess Shale fossil beds in Yoho National Park, British Columbia. Originally created by Teri Rueb in 1999 as one of the first GPS-based sound applications, the installation transforms the trails into a landscape of sound recordings that commemorate personal loss. Walking through the installation is like wandering through a memorial sculpture garden where, instead of visible monuments, visitors weave their way through memorial poems, songs and stories that play in response to their movement through the landscape. This app is designed to work exclusively on-site in Yoho National Park, British Columbia. More information is available at http://www.terirueb.net/trace.