The Almudena Cathedral is the official Cathedral of Madrid and is dedicated to the Virgin of Almudena. Taking over a century to complete, the Almudena is one of the youngest cathedrals in Europe, consecrated by Pope John II himself in 1993. A statue of the pope stands outside of the cathedral to mark the momentous occasion.
The lengthy construction process was due to the change in status from a church to a cathedral a year after breaking ground, which warranted an upgrade in style from Neo-Gothic to Neo-Classic and required new blueprints. Another event that put construction on hold was the Spanish Civil War of the 1930s, during which building stopped entirely until 1944.
What the cathedral lacks in historical significance and architectural merit it makes up for in sheer size - it's 104 m long and 76 m wide (340 ft by 250 ft), with a cupola measuring 20 m (65 ft) across. It is also conveniently located adjacent to the Palacio Real - Royal Palace, which is sure to be on everyone's list of must-see attractions.