In the late XIX century, most of the cities underwent big changes: new avenues were opened through the city center, public transport network were implemented, and the first skyscrapers were built. These changes were promoted by the emerging entrepreneur class, which was able to travel, see the novelties around the world, and bring them back home. One of these entrepreneurs was the swiss Jean Jacques Mercier. One of the leaders in the leather industry, Mercier was also a real estate manager. He was active in Lausanne and, with his interventions, created a new, modern image for the city. In the city center, between 1870 and 1900 he promoted the development of the Flon valley. His project included:
- Docks on the former riverbed,
- An underground railway line, linking the docks to the railway station and to the port,
- A mixed-use building (Mercier House), between the city center and the docks area.
Almost all buildings were shorter than the valley shoulders, invisible from the city center, the only exception being Mercier House.
Smaller buildings gather around it, linked between them by a series of bridges, elevators and walkways. Inside, lots of different activities are gathered: houses, shops, depots, offices, religious communities, sport halls…