Construction of Cologne Cathedral commenced in 1248 and was halted in 1473, leaving it unfinished. Work restarted in the 19th century and was completed, to the original plan, in 1880. It is 144.5 metres (474 ft) long, 86.5 m (284 ft) wide and its towers are approximately 157 m (515 ft) tall. The cathedral is the largest Gothic church in Northern Europe and has the second-tallest spires and largest façade of any church in the world. The choir has the largest height to width ratio, 3.6:1, of any medieval church.
Cologne's medieval builders had planned a grand structure to house the reliquary of the Three Kings and fit its role as a place of worship for the Holy Roman Emperor. Despite having been left incomplete during the medieval period, Cologne Cathedral eventually became unified as "a masterpiece of exceptional intrinsic value" and "a powerful testimony to the strength and persistence of Christian belief in medieval and modern Europe".