During the 20th century, the number of contractor firms responsible for great private and public works in Portugal is limited to less than two dozen. Some of them started their activity in the 1910's and kept working until the turn of the millennium. The founders of these firms were connected by both familiar and business relationships. Exploring the profile of each firm will lead you to a selected number of construction works, done by or with their collaboration. Each of those works is connected to important actors of the construction sector in Portugal: architects, engineers, other firms, institutions, associations and scientific and propaganda literature.