During the middle ages and especially in the early modern period, when Spain conquered large parts of the world, Castile as heartland of the Iberian peninsula used to be one of the richest places on earth. Evidence to this period can still be seen in the immense architectural wealth of the region. Many town have grandiose gothic cathedrals like for example Burgos (pictures 3 and 5) or even smaller beautiful churches like the Convento de Santa Teresa de Jesús in Avila (pictures 2 and 4). Particularly impressive is the “Arco de Santa María” city gate in Burgos, built by Charles V. in the 16th century (pictures 1 and 6).