The rate at which an object weathers is determined by many different variables. For example, compare the two ancient Egyptian structures below.

Compare the obelisk from the temple of Luxor in Egypt (left) and the Egyptian obelisk called Cleopatra's Needle in New York (right).
Both structures were carved in Egypt from the same type of rock more 1,000 years ago. However, the obelisk in New York, which was transported there from Egypt in 1881, has since experienced a much higher rate of weathering. What factors likely sped up the weathering process for the structure that was moved to New York?