Real Fábrica Do Gelo

In the days before refrigeration, ice was a luxury that only the rich could afford, and the Real Fábrica do Gelo in the Serra de Montejunto is a rare surviving place where it was made. The complex dates from the 18th century and was set up to supply ice to Lisbon, about forty kilometres away, where it was used by the royal court, the wealthy, and the city's hospitals, and for preserving food and chilling drinks. The site is in the high ground of the serra, where winters are cold enough for water to freeze overnight and where springs provide a steady supply.

The principle was simple but required careful engineering. Water from the springs and wells was collected in a reservoir and led through channels to a series of shallow stone-walled tanks. On clear winter nights, the thin layer of water in the tanks froze, and workers collected the ice in the morning, breaking it into slabs. The ice was then carried to large, deep, insulated storage pits, where it was packed in layers, covered, and kept cold through the year. In summer, blocks were cut from the stores, wrapped, and carried by mule or cart to Lisbon, often travelling by night to avoid the heat.

Visitors can still see the main elements. The remains include the wells and water-raising works, a reservoir, the freezing tanks laid out in rows, and the roofed stores with thick walls designed to hold the cold. The architecture is practical rather than decorative, built of local stone, and it is easy to understand how the system worked from the layout. Information panels give background to the history, and the surrounding landscape adds to the sense of an industrial site set in open hills.

The Real Fábrica do Gelo makes a good addition to a day in the serra. Nearby are the chapel of Our Lady of the Snows, a viewpoint with long views across the Oeste, and the wild upland scenery of the ridge, with its limestone rocks and spring flowers. Paths and tracks allow short walks, and the area is quiet.

Weather in the serra can be windy and cool even in summer, and mist is frequent, so bring a jacket and wear sturdy shoes, since the ground can be uneven. The site suits history readers, families with curious children, and anyone interested in how people lived before modern technology.