Almost all of Sri Lanka's rock monuments stand far from modern urbanisation, in a splendid isolation that enhances their historical power. Unlike Rome's Colosseum and the Tower of London, they are not circled by traffic and battered with noise, but stand in silent glory within natural landscapes less populated than they were in ancient times.

Take Mihintale, where Sri Lankan Buddhism originated. Mahinda, the son of India's great Buddhist emperor Ashoka, came to Sri Lanka as a missionary in 247BC, staying on a rocky hill near the city of Anuradhapura while he sought a suitable place for meditation away from the urban bustle. While hunting, the story goes, the city's ruler, King Devanampiya Tissa, came across Mahinda rather than a deer and took up the faith.

The site of the encounter became a great Buddhist monastery, encompassing four rocky forested hills, with monks' cells formed out of caves and rocky outcrops. Mihintale, meaning 'Mahinda's Mountain', has been one of the most sacred sites in Sri Lanka for thousands of years and is protected by special laws.

For Buddhist pilgrims and tourists alike, the highlight is the climb up Aradhana Gala or Meditation Rock, a granite hill that juts skywards. A steep, rock-cut stairway that must be climbed barefoot leads to the top, where the wind is wild and the views are spectacular.

Mihintale is about 11km from Anuradhapura, the ancient capital, which is spread out around the edge of the modern city of the same name. For the 1,400 years to the 10th century, with occasional interruptions, Sinhalese kings ruled from here. During that time dozens of temples and palaces arose, but the millennium since has eroded much of the grandeur of Sri Lanka's most extensive and important ancient city.

A great survivor is the temple of Isurumuniya, created by King Tissa. Hollowed out of a large black rock, the temple has several bas-reliefs, the most famous being 'The Lovers', thought to represent the romance of a young prince and a maiden of the 5th century. Another sculpture is a reclining Buddha. Fronting the temple is a black pool that reflects the beautifully carved reliefs of elephants above.

Isurumuniya, like Mihintale, carries you back to the ancient wellspring of Sri Lanka's civilisation. So too does Aluvihara, a monastery set amid dramatic black volcanic rocks that tumbled down from the highlands in some prehistoric cataclysm.

Aluvihara is a site of global importance and a national treasure; the place where the Buddha's teachings became scriptures. Beforehand, for almost five centuries, the Buddha's word had been handed down in speech. More than two millennia ago, monks created Aluvihara and here put the principles of the faith in writing.

Soaring black outcrops rise from palm groves, separated by clefts and hollowed by the caves in which the monks made their cells and shrines. In this secluded setting, meeting in a special conclave in the year 83BC, enlightened monks recited the Tipitakas, as the teachings are called, and painstakingly inscribed them on palm leaves in the sacred Pali language. These became the Pali Canon and the basis of Theravada Buddhism, which is widely practised in tropical Asia. At Aluvihara, palm-leaf scriptures are still produced by monks in residence, although they do live in buildings now.

The caves contain Buddha images and colourful murals. A vertiginous stairway climb takes visitors to a rock-top shrine with great views. Nature, religion and history combine to create a powerful aura.

At Dambulla, on the north central plain, a great temple of painted chambers cowers under a massive granite rock face. King Valagamba, driven out of Anuradhapura in the 1st century BC, took refuge here, it is said. When he regained his throne, he converted the caves into a magnificent temple. Later kings embellished the site, gilding the interiors and giving Dambulla its other name, Ran Giri, or Golden Rock. Sporting colourful frescoes of the Buddha's life and 150 images of him, five cave chambers run for about 200 metres under the rock face, which curves grandly upwards. An access terrace in front of the temple, which is about 150 metres above the surrounding land, commands views across the plain.

Rock drama reaches new artistic heights at nearby Aukana, where a gigantic Buddha image was carved out of a granite rock face. Thirteen metres tall, protected above and to the sides by a brick shelter, the noble standing image with raised right hand, its name meaning 'sun-eating', is always stunning but best at dawn, when the sun's first rays pick out its fine lines.

At Sasseruwa, 11km away, a pupil of Aukana's master sculptor simultaneously attempted his own standing Buddha in rock, but gave up when he saw the quality of the finished Aukana masterpiece.

King Kasyapa was not a man for the reasoned calm of the Buddha: he was more a devotee of the aggressive power of the big cat. At Sigiriya, in the 5th century, the crazed king built a palace fortress on a stark sandstone mesa that juts 200 metres above the north central plain - the Lion Rock. The stairway to the top went through the mouth of a huge brick-built lion's head. Today, visitors begin the climb between two huge lion's paws, carved out of the rock, but the great leonine head is gone. Sigiriya had a vast complex of buildings on its flat summit but now only foundations remain, and the vestiges of huge water basins.

The finest work of art in Sri Lanka, surpassing even the Aukana Buddha, is at Polonnaruwa, the capital city of the 11th to 13th centuries. Here enormous yet exquisite Buddha images were sculpted in granite to form the Gal Vihara temple. Emerging from a low cliff face, a group of three figures, one sitting, one standing and one reclining, bear witness to the masterful artistry and deep faith of this medieval kingdom.

Gal Vihara was not the last example of the remarkable Sinhalese creativity in using and shaping the natural landscape. At Buduruvagala, on a rock face amid forest in the southern highlands, is carved a 15-metre-tall Buddha image attended by smaller bodhisattva figures of Mahayana Buddhist inspiration.

At Yapahuwa in the north, a late 13th century monarch made a rock fortress his capital. At nearby Kurunegala, upon rocky Elephant Hill, the next royal capital was established in 1293.

Few places on Earth match Sri Lanka for its pervasive sense of an ancient culture rooted in profound religious conviction. The island's rock monuments are testament to this culture and are crucial to feeling its power; they should be the bedrock of every visitor's cultural itinerary.