Coin Cave (Grutas Da Moeda)

Beneath the limestone hills near Fátima lies a series of caves that were unknown until the second half of the 20th century. The Grutas da Moeda, the Coin Caves, were found in 1971 by hunters, who noticed an opening in the ground and discovered a chain of galleries behind it. They lie in the parish of São Mamede, in the municipality of Batalha, about two kilometres from Fátima and not far from the abbey at Batalha, in the limestone massif known as the Maciço Calcário Estremenho. The name comes from the nearby hamlet of Moeda, whose name means coin.

This area is a karst landscape, a region where rainwater has been dissolving the limestone for millions of years, carving out underground passages, chambers and sinkholes. The Serras de Aire e Candeeiros Natural Park, which covers much of the massif, contains the largest cave system in Portugal, at Mira de Aire, and many other caves and potholes. The Grutas da Moeda are smaller and quieter than the best-known ones, but they are well developed for visitors, with paved paths, steps and discreet lighting that brings out the shapes of the rock.

A guided tour covers about 350 metres of galleries and takes around forty-five minutes. The temperature inside stays at a steady 18 to 21 degrees Celsius all year, which makes it a cool refuge in summer and a mild one in winter, though the humidity is high, and a light jacket is useful. The caves contain a range of formations, including stalactites hanging from the ceiling, stalagmites rising from the floor, flowstone curtains and columns where the two have met. Several chambers have been given names reflecting their shapes, among them the Nativity Scene, the Red Dome, the Imperfect Chapel and the Spring of Tears, and the guides point out what to look for. Tours are given in several languages, and the commentary explains how the cave formed and how such formations grow, at the rate of a few centimetres per thousand years.

The visit finishes at the surface with a small tasting of local wine and cake, which is included in the ticket price. There is a shop and a bar on site, and the facilities are suitable for families. The route has steps, so it may not suit wheelchairs, though the operators can advise on assistance. Opening hours vary by month, with longer days in summer, and tickets can be bought at the entrance. A shuttle bus has operated from Fátima, so ask at the tourist office.

The caves combine easily with a visit to Fátima's sanctuary and to Batalha's great monastery. Wear shoes with grip, since the floor can be wet. They suit families, curious travellers and anyone who enjoys geology.