The craft of bookbinding began simply, with the use of boards to protect parchment manuscripts. By the 2nd century, sheets of parchment were being folded and sewn together. During the Middle Ages, the practice of making fine bindings for these sewn volumes rose to great heights; books were rare and precious articles, and many were treated with exquisite gilded and jeweled bindings. What is the uncommon practice of binding books in human skin, a technique dating back to the 17th century, called? Discuss
Source: The Free Dictionary
In 1951, the British Royal Navy ship HMS Challenger II surveyed the Challenger Deep trench of the Pacific Ocean, located between Indonesia and Japan, establishing it as the deepest known point of any ocean on Earth. Less than a decade later, a US Navy deep-sea diving submersible descended to the trench floor. There, the crew observed small sole and flounder and noted that the floor consisted of diatomaceous ooze. What is the maximum depth surveyed at the Challenger Deep? 
The Han dynasty ruled China from 202 BCE to 220 CE. During the period of civil strife that followed the fall of the Ch’in dynasty, Liu Pang, a farmer and guerilla fighter, defeated his rivals for the throne and established himself as the first Han emperor. Under Han rule, the harsh laws of the Ch’in were repealed, taxes were lightened, and the absolute autocracy of the emperor was lessened. Which emperor is credited with China’s shift from the Taoist system to the Confucian ideal? 
Light is any wavelength of electromagnetic radiation, though the word is commonly used to refer to the visible light spectrum. The human eye typically perceives electromagnetic wavelengths between 400 and 700 nanometers, interpreting them as a range of colors from red to violet. Light is understood to exhibit both particle and wave properties, and the fundamental particle, or quantum, of light is called the photon. What is the scientific study of light called? 
The tar is a long-necked lute found in Iran and throughout the Caucasus region. Its music was believed to cure a number of physical maladies and induce philosophical moods that compel listeners to reflect upon life. The tar’s double-bowl shape is carved from mulberry wood, and a thin membrane of stretched lambskin covers the top. It has a number of adjustable frets as well as three double courses of strings. Tar, Persian for string, is the root for the names of what other instruments? 
In the early 1600s, three manifestos were published describing an esoteric order founded by Christian Rosenkreuz. The Rosicrucian Order’s secret teachings deal with the occult symbols of the rose and the cross and with mystical writings containing kabbalistic, Hermetic, and other doctrines. Practitioners claim occult powers and employ the terminology of alchemy to expound their mystical doctrines. According to the 17th century texts, Rosenkreutz was born in 1378 and lived for how many years? 
The organs of smell are confined to a small area in the roof of the nasal cavity. Olfactory cells are stimulated when certain molecules reach them, and nerve fibers extend from these receptor cells to the olfactory bulb in the human brain. Smell is one of our most subtle senses, amplifying the sense of taste and detecting tens of thousands of distinct scents. Odor information is easily stored in long-term memory and has strong connections to emotional memory. Why might this be? 
Evidence of human cannibalism suggests that the practice began thousands of years ago. Cannibalism, eating the flesh of the members of one’s own species, is practiced ritually in some cultures, though in Western society people tend to turn to cannibalism only in situations of extreme starvation or when they are mentally ill. Historically, the Aztec Empire is the most famous example of a cannibalistic society. What country was once known as the “Cannibal Isles”? 
Camels, ruminant mammals of the family Camelidae, are well adapted to desert life, as they can live for several days without drinking and their broad, flat, two-toed feet do not sink in the sand. There are two species of true camel, the single-humped Arabian camel, a domesticated animal used in Arabia and N Africa, and the two-humped Bactrian camel of central Asia. The humps, fat stores that provide energy and water when metabolized, also aid in desert survival. How fast can a camel run? 
The term rocket-propelled grenade is actually a misnomer stemming from the Russian acronym for a handheld anti-tank grenade-launcher. The RPG, developed by the Soviets during WWII, is a low-cost, low-tech, direct fire, portable weapon used primarily against unarmored or medium-armored vehicles and personnel. Though it is largely ineffective against heavily armored vehicles and has a low level of accuracy, the RPG has become a favored weapon in what modern conflicts?