29.What does the underlined word "daunting" in PARAGRAPH 5 probably mean?
Passage 2 AMONG CHINA'S greatest art treasures are the Buddhist caves nearDunhuang. Their ancient frescoes and sculptures have survived wars，environmentaldamage，antiquities hunters，and the chaotic Cultural Revolution. Today domestic tourism is the biggest threat: the UNESCO WorldHeritage site has an optimal capacity of 3，000 per day，but peaktimes can see twice that many visitors. The Mogao Grottoes are especially vulnerable to mass tourism. Theirecosystems are fragile. A buildup of humidity and carbon dioxide fromvisitors' breath can lead to flaking and discoloration of wall painting. To preserve the caves，the Dunhuang Academy is pioneering a project to digitize the site. Recently, the Arthur M. Sackler Gallery inWashington，D.C.，offered a tantalizing glimpse at the undertaking. Donning 3-Dglasses, visitors were transported into a breathtaking "virtual"Dunhuang grotto，known as Cave 220. The3-D，interactiveexperience is flooded with vivid color，close-up details，movingimages of flying bodhisattvas，even sound，"Dunhuang ranks as the single most important repository ofearly Chinese art. Here the great cultures of the World-Greek and Roman，Persian andMiddle Eastern，Indian and Chinese-constantly interacted for a millennium，" said MimiGates，who formed the Dunhuang Foundation. "High-resolutiondigitization will provide a lasting record of this artistic treasure forall mankind and can make it accessible beyond China." A dozen years ago，the Dunhuang Academy began cooperating with foregoing institutionsto conserve the treasure. Among the projects，one used a camera tocreate a digital archive of the caves. The results will be used in theacademy which planned$40 million state-of-the-art visitor center which will present virtual tour ofthe caves to save the real site wear and tear. The scope of the project is daunting. It requires20 minutes or so to record a 9-square-meter fresco，and there are 492 caves with murals inside. But theSackler exhibit proved how enthralling the single virtual cave can be. Real caves provide no lightbulbs. Once they reach critical levels ofmoisture and temperature， they are shut to the public. Only a few dozen caves are accessibleat any given time. But the Sackler's virtual tour was different. One of themost popular features was the "magnifying glass"， which canzoom in on，say，a zither depicted in a mural. The instrument appears to pop out ofthe wall，enlarge，and then rotate in space. Visitors can also "flip" backand forth between the intricate Tang-dynasty mural and a later，cruderSung-dynasty fresco. To help Cave 220' s Tang dancer painting magically come to life，two Chineseperformers were flown to the Applied Laboratory for Interactive Visualizationand Embodiment (ALIVE) in a Hong Kong university. For three days the dancerswere filmed performing intricate steps，fluid movements，and carefulmanipulation of long，sinuous ribbons. They appeared in the Sackler tour， dancing as if in midair，clad inbrightly colored Tang costume. ALIVE' s project manager said while he's become intimately familiar withthe images Cave 220，he hasn't been there yet. "I can't wait to visit the real thing".- ALimited.
- BIntimidating.
- CVery broad.
- DRather exciting.