Casa Tóló sits on a 1000 square meter [10,764 square foot] site with a very particular set of characteristics: very long and narrow, relatively steeply sloping, facing south, and with a spectacular view of the surrounding environment. Its primary entrance sits at the top of the hill where a road allows access to the site via car. On approach from this point, you are greeted with a concrete slab and a stair descending into the earth; no building is visible. The descent you are asked to make as a visitor is an “act of faith.” You terrace down through a series of concrete modules, encountering program spaces in sequence, one at a time. At the bottom of the hill, a pedestrian path allows an alternative means of access to the site. Between these two points sits Casa Tóló. It is as much a staircase connecting the two points of access as it is a residential structure. Much like the drawings of M. C. Escher, the building is a game of stairs.
The upper entrance of Casa Tóló. Photograph by Fernando Guerra, FG+SG, courtesy of Álvaro Leite Siza
 Clifford A. Pearson, “In Northern Portugal, Alvaro Leite Siza Vieira Cascades Casa Tolo Down a Steep Slope through Terraced Gardens,” Architectural Record 194, no. 4 (2006): 129.