Son Doong Cave is the world's largest cave, located in the heart of Phong Nha-Ke Bang National Park in central Vietnam. The cave was first discovered in 1991 by a local farmer, but was only fully explored and mapped in 2009 by a team of British cavers. Since then, it has become one of the most popular tourist attractions in Vietnam.

Son Doong Cave is over five miles long, and in some places is more than 650 feet high and 490 feet wide. The cave contains its own river, as well as a unique ecosystem with a variety of plants and animals that have adapted to the cave's dark and humid environment. Visitors to Son Doong Cave can explore the cave's vast caverns and chambers, as well as swim in its underground rivers and lakes.

To protect the cave's delicate ecosystem, access to Son Doong Cave is limited and visitors must obtain permits through licensed tour operators. Tours of the cave typically last several days and involve trekking and camping in the surrounding jungle. Visitors must be in good physical condition and prepared for the challenging terrain.

Despite its remote location and limited access, Son Doong Cave has become a popular destination for adventurous travelers looking for a unique and unforgettable experience. With its stunning natural beauty and fascinating geological history, Son Doong Cave is a must-visit destination for anyone traveling to Vietnam.