The Reading Terminal complex is located in the Market East section of Philadelphia, Pennsylvania. Completed in 1893, the complex houses a massive trainshed as well as a flourishing market that continues to do business today. At the time of its construction, the terminal's single-span arched-roof trainshed was one of the largest in the world. Now the world's oldest structure of its kind, the trainshed has been declared a National Historic Landmark. What is now housed in the trainshed? Discuss
Aerial exploration of the arid tableland surrounding Peru's Palpa valley has revealed a remarkable network of geometric and zoomorphic forms etched in the desert floor. Created by the Nazca, a pre-Incan civilization that flourished from about 200 BCE to about 600 CE, the Nazca Lines span about 200 sq mi (500 sq km). The glyphs are only recognizable as coherent figures from the air, but the Nazca never possessed the technology to view them from that vantage point. Why, then, did they create them?
Found floating in warm seas or washed up on the shore, ambergris is a solid, waxy substance formed in the intestines of sperm whales. Possessing a sweet, earthy odor, it has been used throughout history as a food flavoring and a material for jewelry, though its primary commercial use has been as a fixative in perfumes. However, because ambergris is quite rare and expensive, many of today's perfumes use synthetic replacements. What function does ambergris serve within the whale's digestive tract?