The shrine is known for its medieval seated image of the Madonna and Child, along with its collection of various jewels donated by pilgrims, including Belgian royalty.

On 1 February 1081, an image of the Virgin Mary mysteriously appeared in the garden of a certain Hector, the local lord, and later that day was removed to the parish church.

The miraculous apparition of the statue of Notre-Dame de Tongre was visibly brought by angels through a white, bright cloud into the gardens of the castle of Sir Hector, Lord of the place, at about 11 o'clock in the evening of the first day of February, in the year 1081.

The place immediately attracted large numbers of pilgrims, especially as evidence of wonders and favours bestowed by the Virgin Mary began to circulate.

Several important people visited the shrine of Tongre, including King Philip I of France, Maria Theresa of Spain and Marie Henriette of Austria (Queen of the Belgians).

The most important feast of Our Lady of Tongre is Candlemas Eve, the night of 1–2 February, the anniversary of the apparition in Sir Hector's garden.