(CNN) -- To trace the origins of the David Gareja monastery complex, a series of nearly 30 frescoed monasteries hewn into sandstone, you have to time travel to the sixth century AD, when the Holy Assyrian Father St. David broke ground here to establish an order of Christian monks.

By the Middle Ages, a vibrant spiritual community had taken root with an estimated 6,000 monks in residence -- they'd subsequently be annihilated by Abbas the Great.

Just three monasteries remain active today, presided over by an ever-shrinking cadre of Georgian Orthodox monks.

Built in the sixth century, the photogenic caves of Lavra Monastery, whose lower court houses the tombs of David and his disciple Lukian, are located at the heart of the complex.