It was the first colonial suburb of Buenos Aires. In addition, it was the most distinguished neighbourhood, until 1871, when the yellow fever scared the Buenos Aires elites away from their residences. As it sprang up around the primitive port, San Telmo was soon invaded by the wave of immigrants in the 19th Century, which began to dramatically change the appearance of its streets. The great mansions of the most affluent classes became “conventillos” places where many families lived together after having taken over from their original owners. These immigrants, mostly devoted to crafts and trades, started to leave their imprint and impose their customs on the scene, which has since been characterized by street fairs. It was after 1970 that San Telmo began to be appreciated; the old buildings were refurbished, and many buildings over 100 years old, were declared part of the historical heritage of the city.