Architecture Puzzler #395

In 1830 the initial grid was laid out for the town of Chicago, Illinois, and by 1833 there were 200 houses. The population continued to expand and the city was mostly built of wood-framed buildings until the Great Fire of 1871 gutted Chicago's core. There were 300,000 people living in Chicago at the time of the fire.

The rebuilding of Chicago drove a boom and the population exploded to two million by 1900. This growth created pressure for a taller, denser city. What two inventions in 1850 and 1867 allowed for this upward growth?

Match each energy type with its geologic origins:
1. Natural Gas
2. Oil
3. Coal

A. Formed from organic remains of algae that thrived in the oceans during two warm periods 90 million and 150 million years ago.

B. Also from buried remains of ancient organisms, but unlike "A" above, comes from plants and animals that decomposed at higher temperatures deeper underground.

C. Warm, wet climates 360 million to 300 million years ago gave rise to an explosive growth of swamp plants that were eventually buried, subjected to high temperatures and transformed into this energy source.