Grutas da Moeda, Cave system in São Mamede, Batalha, Portugal

Grutas da Moeda is a limestone cave system in São Mamede, near Fátima, with a 350-metre visiting route that reaches a depth of 45 metres. Its chambers carry names such as Presépio, Pastor, Cascata and Bolo de Noiva, and the entrance and exit lie at different points in the surrounding hillside landscape.

Two hunters discovered the system in 1971 while pursuing a fox, uncovering multiple chambers previously unknown to the public. This chance discovery led to systematic exploration that mapped out the underground passages.

Each chamber has a local name reflecting how people interpret the rock formations, such as Nativity Scene, Shepherd, or Virgin. Visitors can spot these formations and understand the local perspective by walking through the space.

The visitable route is 350 metres long and reaches a depth of 45 metres, with separate entry and exit points in a rocky hillside setting. The interior stays around 18 °C, so bring a light jacket even in summer. The floor can be uneven and slippery in places, making sturdy shoes advisable.

An adjoining scientific center displays a large mineral collection and unusual rock samples extracted from the local limestone layers. These specimens help illustrate how the limestone cave system formed and why it contains such varied geological features.