Describe the place in detail where the 2 families go into hiding

The secret annex was an area in the top attic of Mr. Frank's business. There was a hidden door behind a bookshelf. The Franks and the VanDaans live there for two years. The annexe is a labyrinth of hallways connected to small rooms. Here is a great link where you can see pictures to get a visual,

http://www.annefrank.org/en/Subsites/Home/About-the-house/