The church of Santa María de la Asunción, known in Catalan as Església de Santa Maria de l'Assumpció, is located in the small village of Coll, in the municipality of Valle de Boí. It is currently part of the cemetery and originally belonged to an old Benedictine monastery. It is a Romanesque temple built in the 12th century, using well-carved ashlars, and consecrated in 1110.

In 1992 it was declared an Asset of Cultural Interest, and in 2000 it was included by UNESCO within the group of Catalan Romanesque churches of the Boí Valley, as a World Heritage Site.

The building has a single nave plan, with two side chapels. The nave is covered with a barrel vault supported by toral arches resting on columns. At the foot is a high choir. The apse, with a semicircular floor plan, preserves a rich Lombard decoration on the exterior, also present on the side walls.

The western façade opens with a doorway composed of four archivolts: two plain and two molded with moulding, all of them framed by a wainscot with a checkerboard motif, very characteristic of the Romanesque style. The columns flanking the entrance have capitals decorated with vegetal and historiated motifs. In the keystone of the exterior archivolt there is a chrism of great beauty, considered one of the most remarkable of the whole valley. On both sides, in the spandrels, two doves and two human heads are carved, one of them playing a hunting horn. Above the doorway, a circular oculus opened in the wall brings light to the interior.

The tower rises over the chapel attached to the south wall. It has a square floor plan and consists of four sections; the two upper ones, which serve as a bell tower, were modified in the Gothic period. As is usual in the churches of the Boí valley, this tower follows the proportions of the old minarets: its height is equal to the perimeter of the base.

The doorway preserves the original wooden door with medieval artistic wrought ironwork, testimony to the craftsmanship of the time. Among the liturgical furnishings is a Romanesque altar frontal, currently kept in the Episcopal Museum of Vich, an important piece within the artistic heritage of the church.