A researcher walks past the stair-climbing wheelchair system in a building in Hangzhou, Zhejiang province, July 22, 2012. The special wheelchair, made by researchers from Zhejiang University City College, is designed to help the elder people climb stairs in residential buildings that are not equipped with elevators. The cost for the whole system is between 10,000 to 20,000 yuan. ($1,565 – $3,130). [Photo/Xinhua]

A researcher demonstrates how to use the stair-climbing wheelchair system in a building in Hangzhou, Zhejiang province, July 22, 2012. [Photo/Xinhua]