The lowest temperature theoretically achievable by a system, absolute zero is the point at which substances possess no thermal energy. In 1848, British physicist Lord Kelvin devised a temperature scale that set absolute zero, or 0°K, at -273.15°C. Although absolute zero is impossible to achieve, scientists have brought some substances within a billionth of a degree of 0°K, inducing in these materials odd quantum effects such as superconductivity. Where is the coldest known place in the universe? Discuss
Source: The Free Dictionary
Arguably the first European wars in which hand-held gunpowder weapons played a decisive role, the Hussite Wars were a series of 15th-century conflicts that followed the execution of Czech religious reformer Jan Hus by the Roman Catholic Church. Protests from his followers, called Hussites, who opposed the ascension of Emperor Sigismund to the Bohemian throne, led to three anti-Hussite crusades and a number of armed conflicts. War broke out after what was thrown out of windows in Prague? 
Stari Most, meaning “The Old Bridge,” is a 16th-century bridge in Bosnia and Herzegovina that is believed to have been the largest single-span arch bridge in the world when it was built. Charged under pain of death to construct a bridge of such unprecedented dimensions, the architect that built it reportedly prepared for his own funeral on the day the scaffolding was finally removed. It is now a UNESCO World Heritage Site. For what dangerous tradition do the people of Mostar use the bridge? 
The Comanche were one of the first Native American Plains groups to adopt the horse as a significant part of their culture. By the mid-19th century, they were supplying horses to traders and settlers, but because many of the horses had been stolen, the Comanche were often drawn into battle. The group regularly attacked under the full moon, a condition which afforded them better visibility during nighttime raids and led to the term “Comanche Moon.” How far south were the feared raids carried out? 
Chalk streams are watercourses originating from chalk hills, where rainwater soaks into the ground and is trapped by porous chalk rock. The chalk acts as an aquifer, filtering the water that passes through it and creating a clear, mineral-rich spring lower down on the slope. Because the chalk also regulates the flow of water to the waterway below, there is little day-to-day variation in the amount of water entering the stream. Such conditions make chalk streams an ideal venue for what activity? 
A cytokine storm is a potentially fatal immune reaction that results from an uncontrolled positive feedback loop between immune cells and cytokines, proteins that facilitate intercellular communication. During an immune response, cytokines prompt immune cells to travel to the site of infection as well as stimulate the production of more cytokines. The body regulates this process, but in some cases it becomes inappropriately elevated. What are the primary symptoms of a cytokine storm? 
Baskerville was an American teacher and Presbyterian missionary who led a group of student soldiers against Mohammad Ali Shah during the Iranian Constitutional Revolution in the early 20th century. He is thus often referred to as the “American Lafayette in Iran”—a reference to the French military officer who participated in the American Revolution. He was shot and killed 9 days after his 24th birthday in 1909. What did Persian artisans create in recognition of his courage and sacrifice? 
Macabre enough to earn an appearance in two James Bond films, the garrote, a weapon used for strangulation, was used in Rome as early as the first century. The device takes many forms and can be made from a variety of materials, including chain, rope, fabric, wire, or fishing line. Used throughout history and as recently as 1974 in Spain, garrotes were also developed as execution devices. What nation became the last country in the world to abolish the death penalty by garroting in 1990? 
Click fraud is a type of Internet crime that occurs when a person or computer program imitates a legitimate user clicking on a pay-per-click online advertisement. It is done to generate a per-click charge without having an interested consumer view the ad’s link. In 2004, authorities in California made what was believed to be the first click fraud arrest, detaining a man who had attempted to blackmail Google with a click fraud program he created. Why were the charges dropped without explanation? 
The word barbecue can refer to many things: a specific cooking method, cooking apparatus, type of food, or party that includes such food. For many, the word brings to mind smoky meats flavored with a variety of sauces, rubs, and seasonings. However, the origins of both the word and activity are somewhat obscure. Most etymologists believe it was derived from the term “barbacoa,” which means “sacred fire pit” in the language of the Taíno people of the Caribbean. What are some other explanations?