As a part of the new Spanish high speed railway line (AVE) connecting Madrid, Barcelona and the French border, currently a tunnel with a length of 5.6 km is built under the city centre of Barcelona. The tunnel line passes directly next to the famous church of Sagrada Familia and a building called “Casa Milà”. Both buildings belong to the World Heritage Properties of the UNESCO. To ensure the highest possible safety for these extraordinary historical buildings special requirements in control and construction had to be fulfilled during the tunnelling process. The tunnel is built with a tunnel-boring machine using an earth pressure balanced shield. The church of Sagrada Familia and Casa Milà have already been passed. The maximum measured settlements of Sagrada Familia and Casa Milà induced by the tunnel construction were in the range of the measurement accuracy. Some of the extensive data of the geotechnical and geodetic monitoring is presented focusing on possible influencing factors for the evolution respectively the prevention of surface settlements.