Located on the Silk Road, the 1,500 year-old works of art once formed the centerpiece of one of the world's largest Buddhist monastic complexes. At one time, thousands of monks tended countless shrines in the niches and caves that pierced a kilometer-long cliff face.

Since the destruction of the statues by the Taliban regime, restoration experts have been endeavoring to secure the remains and restore access to the statues. Examination of several hundred fragments from the 55m and 38m tall statues has yielded some surprising insights.

"The Buddhas once had an intensely colorful appearance," explained Professor Erwin Emmerling, from the Technische Universitaet Muenchen, in Germany. He discovered that prior to the conversion of the region to Islam, the statues were over-painted several times, presumably because the colors had faded. The outer robes, or sangati, were painted dark blue on the inside and pink, and later bright orange, on top. In a further phase, the larger Buddha was painted red and the smaller white, while the interior of the robes was repainted in a paler blue.

Previous attempts to determine when the statues originated were estimates based on the style of the Buddha's robes or similar criteria. Mass spectrometer tests now date the construction of the smaller Buddha to between 544 and 595 and the larger Buddha between 591 and 644.

The conservators working on the project have stacked the ruins in temporary warehouses in the Bamiyan Valley. Larger pieces have been covered over in situ. "However, that will only last for a few years, because the sandstone is very porous," Emmerling explains. He adds that conventional methods of conservation are out of the question. "On this scale, under the climatic conditions in the Bamiyan Valley, the behavior of the synthetic resins usually used would vary too widely relative to the natural rock," said Emmerling, who instead hopes to refine a new process that injects an organic silicon compound into the stone.

The scientists consider a reconstruction of the smaller Buddha to be possible, but the larger Buddha, with a depth of around 12 meters, may be more problematic. The smaller figure with a depth of around two meters was more along the lines of a relief, says Emmerling. However, even to restore the smaller figure, there are political and practical obstacles to overcome. Conservation of the fragments would require the construction of a small factory in the Bamiyan Valley - alternatively some 1,400 rocks weighing up to two tons each would have to be transported to Germany. A conference to be held in Paris this week will further consider the fate of the fragmented Buddhas.