Named after the Icelandic poet and clergyman Hllgrimur Petursson, the Hallgrimskirkja or the Church of Hallgrimur is the largest church in Iceland with a seating capacity for 1200 people in the nave. With its magnificent high steeple rising 244 feet (74.5 m) in the sky, it is the crown on Reykjavik, one of the best-known landmarks and is visible throughout the capital city.

The site of the church, situated on the Skolavorduholt hill, overlooking the centre of old Reykjavik, was kept reserved early this century for the purpose of building a large church, so that in future it can serve the rapidly growing eastern part of the town. Finally, State Architect Gudjon Samuelsson, who designed many buildings to be seen throughout the country like, the main building of the university, the National Theatre, the Roman Catholic Cathedral in Reykjavik and the Church of Akureyri, was commissioned in 1937 to design the Hallgrims church.

Samuelsson intended to use motifs and materials from the Icelandic nature and landscape with basalt formations, to resemble the trap rocks, mountains, icecaps and glaciers, which dominate Iceland's landscapes and to create a style of national architecture, like the other Nordic countries. He completed the design in 1940, which created controversy, especially due to its gigantic size and the towering steeple. However, despite adverse criticism, the design remained unchanged, as a large number of people were determined to give it a shape.

The project started in 1945 and it took long 41 years to complete the construction in 1986, just in time for the 200-year anniversary of Reykjavik. However, the Crypt under the Choir was consecrated as a chapel congregation in 1948, while both the wings, along with the steeple were completed in 1974, which provided the congregation with a better place for worship. The nave was consecrated in 1986 on the bicentennial of the city of Reykjavik.

The interior of the huge church measures 18,040 sq ft (1676 m). Leifur Breidfjord, who designed and made the main door of the church, is also responsible for the large, stained window above the front entrance of the church. The beautiful pulpit, decorated with symbolic representations of the Trinity and the Greek initials of Christ (X and P) is surrounded by Alpha and Omega. The statue of Christ, depicting Christ at the moment the Spirit descends on him at his baptism was created and donated by the sculptor Einar Jonsson in 1948.

The church also possesses a copy of Gudbrandsbiblia, the first Icelandic Bible, printed at Holar in 1584. Apart from that, there are three big bells in the steeple and a carillon of 29 bells, inscribed with the names of the donors and the person in whose memory the gifts were made. The big bells carry the names Hallgrimur, Gudrun and Steinunn, named after the Reverent, his wife and a daughter, who died young.

The Church of Hallgrimur houses a large German organ, built by Johannes Klais in Bonn. Inaugurated in December 1992, the grand organ with 72 stops, by far the largest in Iceland, is equipped with 5275 pipes, four manuals and pedals, stands 15 meters high and weighs around 25 tons. A new console for the big organ was installed in the nave in 1997 and the older and much smaller choir organ with 10 stops, built in 1985 by Theodor Frobenius & Sønner AS organ builders in Denmark, is in the nave and still in use.

The steeple of the church is open to the public and can be used as an observation tower with the help of a lift, which takes the visitors to the viewing deck for experiencing the breathtaking panoramic view of Reykjavík and the surrounding mountains