Planet

Mountain Biking

In many countries, the bicycle was supplanted by motorized vehicles as the preferred mode of transportation by the early 20th century. However, the mountain bike, introduced in the 1970s with rugged features meant to increase durability and improve performance in rough terrain, has done much to renew interest in cycling. Today, mountain biking is recognized as a sport in its own right and has a vast community of enthusiasts that spans the globe. When did mountain biking debut at the Olympics?

Mary Cassatt

Cassatt was an American figure painter and etcher. As a young art student, she moved to Paris, where she was inspired by the work of Edgar Degas, with whom she developed a friendship. She allied herself with the Impressionists early in her career, but, in the late 1880s, she began experimenting with other styles and techniques. Many of Cassatt\'s best-known works are intimate depictions of mothers and children. What cause did she take up when cataracts put a stop to her painting career?

Nuclear Submarine USS Scorpion Sinks, Cause Unknown

On May 21, 1968, the crew of the US Navy\'s Scorpion submarine engaged in communications with land stations. Six days later, the submarine was reported overdue. After an unsuccessful search, the Scorpion and its crew were "presumed lost." However, in October, a Navy research ship located sections of the submarine\'s hull in approximately 10,000 feet (3,048 m) of water about 400 miles (644 km) southwest of the Azores. What are some theories about how the Scorpion may have sunk?