Simplify the following text for a Grade 9 native English-speaking person.
Original: There are over one hundred brick Gothic castles in northern Poland , Baltic states , and western Russia , and many smaller buildings .
Simplified: In Northern Germany , Netherlands , Denmark , Baltic countries and northern Poland there was no good building stone , but there was clay for making bricks and tiles . So many of these countries have Brick Gothic churches and even Brick Gothic castles .