Complex sentence: Located in the heart of the black land of Mordor and approximately 4,500 feet (1.4 km) high, it represents the endpoint of Frodo Baggins' quest to destroy the Ring which is recounted in "The Lord of the Rings".
Split into simpler sentences: Located in the heart of the black land of Mordor and approximately 4,500 feet (1.4 km) high. The mountain represents the endpoint of Frodo Baggins' quest to destroy the Ring which is recounted in "The Lord of the Rings".