4. Granite Mountain, Arizona, USA
Media Source: mentalfloss.com
The genealogical library is buried 600 feet underneath the Granite Mountain. The library includes 3.5 billion images, from census records and immigration papers on a microfilm. All of these collectibles are from all around the world. The library is kept safe by armed guards and by a 14-ton, nuclear-blast-resistant door. Some say that inside there might be a record with your name on it.