The Barabar Caves are the oldest surviving rock-cut caves in India, mostly dating from the Maurya Empire (322–185 BCE), some with Ashokan inscriptions, located in the Bela Ganj Block of Gaya district, Bihar, India, 24 km north of Gaya.

These caves are situated in the twin hills of Barabar and Nagarjuni. Caves of Nagarjuni Hill sometimes are singled out as Nagarjuni Caves. These rock-cut chambers date back to the 3rd century BC, Maurya period, of Ashoka (273-232 BCE) and his son Dasaratha Maurya. Though Buddhists themselves, they allowed various Jain sects to flourish under a policy of religious tolerance.

The caves were used by ascetics from the Ajivika sect, founded by Makkali Gosala, a contemporary of Gautama Buddha, the founder of Buddhism, and of Mahavira, the last and 24th Tirthankara of Jainism. Also present at the site are several rock-cut Buddhist and Hindu sculptures.

Most caves at Barabar consist of two chambers, carved entirely out of granite, with a highly polished internal surface and exciting echo effect. The first chamber was meant for worshippers to congregate in a large rectangular hall, and the second, a small, circular, domed chamber for worship, this inner chamber probably had a small stupa like structure, at some point, though they are now empty.

The caves are famous internationally, as they featured in the book A Passage to India by English author E. M. Forster.

Barabar Hill contains four caves, namely, Karan Chaupar, Lomas Rishi, Sudama and Visva Zopri. Sudama and Lomas Rishi Caves are the earliest examples of rock-cut architecture in India, with architectural detailing, made in the Mauryan period, and became a trend the subsequent centuries, like the larger Buddhist Chaitya, that were found in Maharashtra, as in Ajanta and Karla Caves, and greatly influenced the tradition of South Asian rock-cut architecture. Barabar caves have magnanimous arches which are few in ancient history.

• Lomas Rishi cave: The arch-like shape facade of Lomas Rishi Caves, imitate the contemporary timber architecture. On the doorway, a row of elephants proceed towards stupa emblems, along the curved architrave.
• Sudama cave: This cave was dedicated by Mauryan Emperor, Ashoka in 261 BC. The arches of Sudama cave are of bow shape. The caves consist of a circular vaulted chamber with a rectangular mandapa.
• Karan Chaupar(Karna Chaupar): Consists of single rectangular room with polished surfaces, contains inscription which could be dated to 245 BC.

Visva Zopri: Reachable by Asoka steps hewn in cliff, consists of two rectangular rooms.

The cuttings of Barabar caves are so sharp that they can be compared with the laser cutting of modern days. These caves are so beautiful and adoring that when one see from inside it looks just like wooden crafting. For the writing of the history of the Buddhism these caves plays a very important role. There are several Jataka stories that have been portrayed over the walls of Barbar caves that help in knowing and understanding the history and development of the different phases of the Buddhism.

Source:

http://www.gaya.net.in/barabar-caves-in-gaya

http://en.wikipedia.org/wiki/Barabar_Caves