This lecture explores the Sublab at the École Polytechnique Fédérale de Lausanne in Switzerland, a laboratory focused on underground architecture, aiming to redefine the underutilized territory as a new potential space for urban expansion. The concept of 'Groundscape' is introduced as a new semantic field, merging 'ground' and 'landscape' to reflect on the potential of underground spaces in our cities. The lecture showcases the work of students, architects, and engineers from EPFL who become researchers and experts in Groundscape, contributing to numerous projects and international exhibitions.