A very extensive site about castles in Europe and especially Germany. In German.

An extensive site about French castles. In French.

A nice site about with beautiful b/w pictures of European castles. In German.

A great site with lots of beautiful pictures of fortifications in an relatively unknown area.

Castles in the Soria province in Spain. In Spanish.

Castles in the Alsace province in France. In French.

Nice site about castles in Spain. In Spanish.

Another extensive site about castles in Spain. In Spanish.

Castles in Switzerland
Extensive site of Swiss castles. In German.

Castles of Britain
Nice and educational site about castles in Britain.

Dolmens in the Netherlands. A very complete site with pictures of all dutch dolmens. Both in Dutch and English.

Bordermarkers of the Netherlands. With pictures of áll existing Dutch bordermarkers! In Dutch.

Site about the ex-island of Wieringen in the north of Holland. Both in Dutch and English.

Site about the drowned island of Orisant. In Dutch.

Virtual Ani. A great site of the ruined, medieval ghost city of Ani on the Armenian/Turkish border.
Lots of beautiful pictures.

Ok, this is not about a historical or Dutch subject but about another small hobby; tracking Eurobills.