This video shows some highlights from a field test Prof. Tim Barfoot’s group conducted in June 2016 at an old sand and gravel pit in Sudbury, Ontario, Canada. Tethered Robot eXplorer (TReX) was designed to operate on steep and rough terrain by using a tether that carries part of its load, provides power, and transmits data to an operator. They demonstrate that TReX was able to descend down several cliffs and other steep terrain to build 3D models.