Loevestein Castle (Slot Loevestein in Dutch) is a medieval castle built by the knight Dirc Loef van Horne (hence 'Loef's stein') between 1357 and 1397. It was built in a strategic location where the Maas and Waal rivers come together. At first it was a simple square brick building, used to charge toll from trading vessels using the rivers. In the 16th century (around 1575, orders given by William the Silent) it was expanded to a larger fortress surrounded by earthen fortifications with two (later three) stone bastions on the northern side, two moats, an arsenal, and housing for a commander and soldiers.
Loevestein changed hands twice between the Northern Dutch and the Spanish (December 9, 1570 it was taken by the Geuzen, ten days later Spanish again, and from June 25, 1572 Dutch till this day), the warring parties of the day. The castle became a prison for political prisoners in 1619. One famous inmate was the eminent lawyer, poet and politician Hugo de Groot (Hugo Grotius) often presented as the 'father of modern international law', who was serving a controversially imposed life sentence from 1619. In 1621 Hugo de Groot managed to pull off a daring escape in a book chest. The idea for this escape came from his wife Maria van Reigersberg (also living in the castle). He subsequently became the Swedish Ambassador to France for 10 years. Another high profile inmate was the English Vice-Admiral George Ayscue.
Until the Second World War Loevestein Castle was part of the Nieuwe Hollandse Waterlinie, the main Dutch defense line that was based on flooding an area of land south and east of the western provinces. Currently the castle is used as a medieval museum and function centre.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.