Living in a city, it is often easy to forget that there is soil beneath our feet, that the land we tread is undulating and criss-crossed with ancient streams. Too often the streams are bull-dozed and filled in with the tops of hills. Too often the hills are bull-dozed and used to even out old streams. Frequently, the soil and the vegetation is papered over with concrete, with bitumen and with intricately laid bricks. Humans have a compulsion to keep the jungle at bay.
But the jungle is persistent. Roots of trees crack the concrete. Wind blows soil into cracks. Birds drop seeds into cracks. Small trees grow. The jungle returns. With a vengeance.
Beneath many cities, bubbles the molten core of planet Earth, alert and restive, patiently biding its time. In many cities across the globe, the populace has received grim reminders of the power of the natural world.