Almudena Cathedral (Santa María la Real de La Almudena) is next to the Royal Palace in Madrid. It is very different from all the other cathedrals I have seen in Spain. Probably because it is relatively new; Pope John Paul II consecrated it in 1993.
Plans to build a cathedral in Madrid dedicated to the Virgin of Almudena were discussed as early as the 16th century. However, expanding the Spanish Empire took priority and Madrid remained without a cathedral for many years. The construction of Almudena finally started in 1879. Building work was stop/start with delays due to changes in architect and the Spanish Civil war. A large Romanesque crypt was completed and opened in 1911. The cloister area was finished in 1955 and the facade in 1960.
On June 15, 1993, Pope Saint John Paul II came to Madrid to dedicate and consecrate the cathedral. The Almudena Cathedral had taken 110 years to build.
The interior of the cathedral is Neo-Gothic. The floor is a combination of green serpentine Granada marble and yellow polished travertine. The altar is also of green serpentine marble. To its right is the episcopal chair, carved in walnut, made by Ramón Fonollosa in 1885.
Behind the main altar, you will find the figure of the Crucified Christ by Juan de Mesa commissioned by the Imperial College of Madrid. Both the cross and the choir stalls located either side of the altar originate from the collegiate church of San Isidro.
The Almudena Cathedral is very different from the other cathedrals I have seen in Spain. My personal favourite is Sevilla Cathedral, but your preferences may be different.