Sant Climent de Taüll (Vall de Boí)
Sant Climent de Taüll, also known as the Church of St. Clement of Tahull is a Roman Catholic church. It is a form of Romanesque architecture that contains magnificent Romanesque art. Other influences include the Lombard and Byzantine styles, which can be seen throughout the exterior and interior of the building. The church is a basilica plan structure with three naves,(each of them with a terminal apse) and large columns separating the side naves. Connecting to the church is a slim bell tower that has six floors plus a base. The artwork inside the church include the famous mural paintings by the Master of Taüll (contained in the different apses and the keys of the arches), as well as the wooden alter frontal. These works of art represent different aspects of Christianity that can also be found in many other works of art. The most famous fresco, of Christ in Majesty in the Apse of Sant Climent de Taüll main apse of the church, has been moved to the Museu Nacional d'Art de Catalunya in Barcelona.
Sant Climent de Taüll is located in Taüll in municipality of Valley of Boí, in the province of Lérida, Spain. The exact date of construction is unknown however the church was consecrated on December 10, 1123. In 1064, before Sant Climent de Taüll was constructed, it was an object of sale and exchange by several different counts. The different counts include the Counts of Pallars Sovereign (I Artau and his wife Lucia), the Counts of Pallars Jussà (Ramon IV and his wife Valença), as well as the castle Erill and other possessions. Sant Climent de Taüll was devoted to and consecrated by the Bishop of Roda-Barbastro, Guillem Ramon. One day later Guillem Ramon also consecrated Santa Maria de Taüll, another Romanesque church located near Sant Climent de Taüll.
Sant Climent de Taüll is a Romanesque style church greatly influenced by the Lombard style, which can be seen through its exterior decoration. The bell tower is an example of Byzantine influence because it stands out for its verticality. The church was intended as a place for Christian worship, unlike other churches of the time, which were intended as a pilgrimage. The artwork in Sant Climent de Taüll was important in bringing the art into the public atmosphere. The main work of art is the mural painting, located on the central apse of the church. This mural painting was painted by a painter, whose identity is unknown, but is referred to as Master Taüll. The altar-frontal is another work of art found in the church, and it was created by a native Catalan artist. It is possible that the altar frontal was made in a workshop in La Seo de Urgel
Sant Climent de Taüll is the largest, most well preserved, and has the most outstanding architecture out of all the churches in the Valley of Boí. The church is a basilica plan structure, that has three naves (each of them with a terminal apse), and large columns separating the side naves. One of the doorways opens on the west side of the building, with the remains of what might have been a porch. The other openings are located on the south side and the on the access tower. The facades of the church do not have any decoration, however the apses have simple Lombard decorations and are built with stone and brick. The central apse on the exterior is decorated by groups of four arches, separated by half columns. The apsidioles (apses on either side of the central apse), have groups of three arches instead of four, with each of the apses having one window each. In addition, the central apse has three arched windows located on ground level and two portholes on either side of the central apse.
In the south corner of the church there is a tall, slim bell tower that is a square plan with a prism-shaped roof. The tower has seven floors (base floor plus six), where the base is the foundation of the entire structure. As we ascend through the bell tower, the structure becomes lighter in weight because of the larger windows near to top of the tower. On each of the plants there is the same amount of windows on the four sides of the tower, and there are five arcs in the space around the windows.
Inside Sant Climent de Taüll three naves are separated by three cylindrical columns. The columns are made of amalgamated stone, which support the arcades and the roof of the church has wooden beams. The first column on the north side of the church near the apse, was found to have the inscription of the consecration of the church. This document is painted with white letters on red and black background and is now preserved in the National Museum of Catalan Art. The interior of the church (the walls of the naves, apses and columns), were originally covered with polychrome decoration. In the early twentieth century, the National Art Museum of Catalonia in Barcelona took the mural paintings inside the church to protect and preserve them. An exact replication of the mural painting on the central apse was made in place of the original. However, the original mural painting on the northern apse can only be seen in the National Art Museum of Catalonia. The removal of the mural paintings was done by applying horsehide glue. The hardened glue was then peeled off, carrying the pigments of the mural with it.
A mural paintings is an art that is painted and applied to the wall, ceiling or other permanent surfaces that are sufficient in size. The technique used is called fresco, where the paint is applied on plaster on walls and/or ceilings. The pigment is mixed with water on a small layer of wet lime mortar or plaster, where it is later absorbed. After several hours, the plaster dries while reacting with the air. This creates a chemical reaction making the pigment stick to the plaster. Over a long period of time, the painting will end up with brilliant colors.  One of the main mural paintings is four meters in diameter located on the central apse. There are several holes (due to excess moisture), on the original mural painting on the central apse that have not been restored. A polychrome wood carving and other objects are also located inside the church, some of which were successfully restored. 
Sant Climent de Taüll had the earliest wooden altar-frontal, which was 1.36 m by 0.98 m in size. When it reached Barcelona it was covered with a coat of paint which was removed. An inscription on the center of the upper frame shows that in the year 1579, the altar-frontal was repainted. The wooden alter frontal is enclosed by a narrow wooden frame, which is held together at the four corners with wooden dowels. The figures were each carved separately, and then were attached to the back of the panel using wooden dowels. The four side divisions contain a blind arcade of three arches, where there are figures located directly underneath. The arches are formed from tall capitals, which are supported by slim colonnettes with torus molding, as well as a high base. The upper right corner is slightly damaged, though some of the original colour can be seen on the lower left corner of the antependium. The frame was painted green and yellow, and there are indications that the frame originally had some stucco ornament. The wooden alter frontal use to have four symbols of the evangelists that had filled the outside of the mandorla, however these have been lost.