The photographs above were taken in the city of Jaipur, India (in 2007 and 2006, respectively). The one on the left is of a thick stone wall from Jaipur’s historic walled city, the one on the right is of a conglomerate rock located inside a city park. One major difference between these two is of age, the wall is less than 300 years old whereas the rock is estimated to be about 1600 million years old (yes!). Many (man-made) walls and structures in the historic Jaipur walled city are in a state of decay, some have crumbled, yet the rocks in the nearby Aravalli hills look as good as new! Isn’t nature’s ability to maintain or sustain itself amazing?