The Magura Cave - One of the largest caves in the country and galleries exceed 2000 meters. Includes photos of formations, geology and history. Located 32 km northwest of Belogradchik. - http://www.magura.hit.bg/
Caving in Bulgaria - Describes four caves in the Trigrad region. Includes photos and contact information. - http://www.motoroads.com/tours_bulgaria_caving.html