After surveying more than one million square metres of land at all 31 Olympic venues in the city, archaeologists said they had discovered more than 700 tombs and 1500 artefacts, from jade belts to Ming dynasty glassware. The aquatic centre was built 100 metres further north than planned to avoid a Taoist temple. Kong Fanzhi, head of the Beijing Relics Preservation Bureau, told reporters that the government has attached great importance to relics. "We have taken several measures to preserve these cultural relics. For example, we tried to avoid those relics when picking up location of the Olympic venues. This temple you are seeing right now is here because we moved the swimming center up to the north for 100 meters. We also stayed way from a tomb site and converted it into a national park. Before doing any construction work, we would have experts do some research and excavation," said Kong. "We took these measures to make our construction work easier and preserve these cultural relics at the same time. We were trying to find a balance between these two goals," said Kong. The tombs date from the Han Dynasty (206 BC-220 AD) to the Qing Dynasty (1644-1911) and include several Ming Dynasty (1368-1644) examples unearthed during construction of the shooting range.