Excavation of a metro tunnel in the historical centre of Athens (Gazi/Technopolis area) in soft rocks produced considerable tilting, up to 7.5 ‰, but no damage to three isolated historical brick chimneys, 26–34 m high. Tilting was derived from coordinate changes of control points at the top of the chimneys measured from a remote total station and permitted to understand that during the tunnel excavation, the control points on the chimneys were moving roughly along semi-circles with radii up to 20 cm and that the overall motion of the structures can be simulated by inverted half-cones. While deformation of the ground due to tunnelling was so far usually assumed as a 2-D effect approximated by a Gaussian function, evidence presented clearly indicates a 3-D deformation (tilting of chimneys as rigid structures in different directions), in full agreement with new theoretical models of ground deformation due to nearby excavations (ground loss). Measurement of the 3-D tunnelling-induced ground deformation became for the first time possible for two reasons: first, the Gazi historical chimneys are isolated slender structures functioning as huge tiltmetres amplifying the amount of local ground deformation; in most other cases, this deformation is obscured/compensated by the response of bulky buildings. And second, the use of geodetic total stations (electronic theodolites) permits remote measurement of changes of 3-D coordinates of control points with nearly millimetre accuracy. Observed amount of tilting of the chimneys is several times larger than the accepted threshold of failure of structures during tunnelling/excavations, and this due to their foundations, limited in dimensions and directly on the ground, practically not subject to differential displacements. This result is important for future underground works in the vicinity of isolated slender structures such as towers, bell towers and minarets.