Madrid became the capital of Spain and her empire in 1561. The capital had previously been at Toledo under Holy Roman Emperor Charles V.

The Royal Palace was built on the site of the old alcázar (Moorish castle) in the 1700s by the Italian Giambattista Sacchetti. The main façade includes statues of Aztec king Montezuma (on the left) and Inca king Atahualpa (on the right).
The Escorial (the Monastery Of San Lorenzo) lies in the Guadarrama mountains north of Madrid. It was commissioned by Philip II (he of the Spanish Armada) from Juan Bautista De Toledo and Juan De Herrera. It takes the form of St. Lawrence's gridiron, and Herrera's extremely severe style was carried to the New World, inspiring buildings such as Mexico Cathedral. If the Palace Of Versailles is the seed of the megalomania of the totalitarian regimes of the 20th century, then the Escorial is the origin of their architectural brutality.

Burgos is a major destination on the Way Of St. James, and is the birthplace of El Cid (who fought the Moors).

Construction of the cathedral began in 1221. It has been suggested that the original architect was Richard from English Aquitaine, brought by Eleanor of Castile (daughter of Henry II of England). The later work, comprising the west towers, the Constable's Chapel and the crossing tower, was done by three generations of architects from Cologne - Juan, Simón and Francisco De Colonia. Between them they established the external character of the church - a fantastical vision of turrets and spires.
The sublimely beautiful Constable's Chapel was begun in 1482 by Simón De Colonia and continued by his son Francisco. Along with the cathedral crossing and the Chapel Of The Presentation, it is one of the few glazed vaults in the world.

Seville (Sevilla), capital of modern Andalusia, was taken from the Moors in 1248.

Seville Cathedral is the largest by volume in the world, with one of the highest nave vaults (just a foot lower than Amiens). It occupies the site of the former mosque, of which only the cloister and minaret (belltower) remain. Work began in 1433 (supposedly by Carles Galtes De Ruan i.e. Rouen) after the 1401 declaration by the canons that it would be "so beautiful and large that those who see it would think [the canons were] mad."
The tomb of Christopher Columbus dates from 1891, after his remains were moved over the centuries, from Spain to Santo Domingo (Hispaniola) to Cuba and back to Spain.
The Plaza De España and nearby buildings date from the 1929 Ibero-American Exposition.

Córdoba (Cordova) is chiefly of interest for its history as the capital of the Islamic kingdoms on the Iberian peninsula, which lasted from the 700s until defeated by the Catholic Monarchs, Isabella and Ferdinand, in 1492 (although Córdoba itself was conquered in 1236).

Built as a mosque in several stages from 786 onwards and largely retained by the conquering Spaniards (unlike what happened in Seville), the Islamic structure of the Mezquita was nonetheless stamped with the imprint of a gothic cathedral in 1523.
The Mezquita is an extraordinary building in which political, religious, cultural and architectural contrasts are powerfully manifest. The dimly lit rows of countless Moorish columns are sporadically interrupted by the thrust of a heavy gothic buttress. Visitors, drawn to a distant white light, cross into the dazzling pearlescent heart of the cathedral.