Basilica of Our Lady, Maastricht

At the location of the Onze Lieve Vrouwebasiliek (Basilica of Our Lady) there was already a church in the 5th century. This was probably the oldest Christian church in the Netherlands and may have been built on the remains of a Roman temple. In the foundation of the western part you can still find two enormous stones that come from the Roman fort. The Onze Lieve Vrouwekerk or “Slevrouwe” as it is called by the Maastrichters, is a fine example of Roman architecture.

Various extraordinary works of art can be admired in the church. In the treasury there are also numerous ecclesiastical objects of art and ecclesiastical handicrafts such as richly embroidered cope with chasuble, the so-called "Levietenkleed" from St. Lambertus, the penultimate bishop of Maastricht, relics in magnificent stands, processional flags, church silver, sculptures and much more.

Source: besuchemaastricht.de/orte/2112651889/onze-lieve-vrouwe-basilica

The Liebfrauenbasilika (Basiliek van Onze-Lieve-Vrouw-Tenhemelopneming) is a Catholic church in the center of the Dutch city of Maastricht.

de.wikipedia.org/wiki/Liebfrauenbasilika_(Maastricht)

At the end of the 10th century, the Church of Our Lady was built by the Liège Prince-Bishop Balderic. The westwork on the square dates from that period. The nave was renovated in the 12th century and the courtyard with arched cloister was added in the 16th century. The 15th century Merode Chapel was initially used as a baptismal chapel and later as a devotional chapel for Mary Star of the Sea.
Basilica is free to enter.
Take your time and don't forget to visit the crypt.
Delve into the spiritual past of Maastricht.