The Sanctuary of Our Lady of Lourdes is the sprawling religious complex built around the grotto following the Church's official recognition of the apparitions in 1862. It encompasses three basilicas stacked on and around the rocky promontory: the Basilica of the Immaculate Conception at the top, the Rosary Basilica at the base with its distinctive neo-Byzantine dome and mosaics, and the underground Basilica of St. Pius X capable of holding 25,000 people — one of the largest churches ever built.
The Esplanade des Processions, the broad approach to the basilicas, is where the famous nightly candlelight processions take place each evening in summer. Tens of thousands of pilgrims process with lit candles, singing Ave Maria in dozens of languages. Even visitors with no religious convictions often find this unexpectedly moving. The sanctuary also maintains the Baths, pools fed by the spring water where pilgrims are immersed as an act of faith — there are often long queues, but volunteers manage them efficiently.