This highly controversial building -- built on the site of Santa María de la Almudena, which in turn occupied the site of Madrid's first Muslim mosque -- must be one of the longest delayed projects in modern times (110 years from inception to conception, in fact). Work began on the cathedral in 1883 following a neo-Gothic plan by the Marqués de Cubas. The first thing to be completed was the crypt, which today retains the 16th-century image of Madrid's patroness the Virgen de la Almudena. After that, progress was halted until 1944, when a new architect Fernando Chueca took over, introducing a neoclassical style. It was eventually finished in 1993 and graced with a visit from the Pope. The bright interior reflects an uncertain blend of hybrid styles and its stained-glass windows are of the "pop art" variety; the windows were recently revealed to have been copied. (In defense, their creator claims they were "a vision from God.") The building was given a much-needed shot in the arm with the sumptuous wedding of Prince Felipe and Doña Letizia (a former newscaster) in May 2004, the first such royal event in nearly a century.

Copyright: Excerpted from Frommer's Madrid, 3rd Edition, (c) 2008, Wiley Publishing, Inc.

Find Hotel Deals on Yahoo Travel»