During the 1600s to 1800s, Spanish and then later Mexican silver dollars were the currency of choice for foreign trade in Japan and China, and entered into circulation in those countries for domestic trade as well.

What were these "pieces of eight" doing so far from their mint sites? Mexican silver dollars were valued for their purity and consistency; thus, they became the standard for trade in East Asia.

By the late nineteenth century, China was minting its own silver and gold coinage, and Japan began to issue paper currency instead.

See samples of Mexican silver dollars used in Chinese trade, and read an 1878 New York Times article about currency problems in the Far East.

Photo by woody1778a on Flickr.com.

On October 31, 1984, Indian Prime Minister Indira Nehru Gandhi was assassinated by two of her Sikh bodyguards.

The attack likely was retaliation for Gandhi's order for the Indian Army to attack the Sikh's holiest site, the Harmandir or "Golden Temple," in September of 1981. At the time, Gandhi was trying to suppress a separatist movement in the Punjab region.

In the attack on the Golden Temple, as many as 3,000 people were killed.

Indira Gandhi was the first, and so far only, female prime minister in Indian history. She was the daughter of Jawaharlal Nehru, India's first prime minister.

Contrary to popular belief, her husband, Feroze Gandhi, was not related to the Mahatma Gandhi. She did know the Mahatma from childhood, however.

Photo from the U.S. Department of Defense via Wikipedia.

Science popularizer and author "Dino Don" Lessem has a new exhibit running, but this one isn't about dinosaurs.

The Denver Museum of Nature and Science is hosting his exhibition on Genghis Khan, which runs from October 16, 2009 to February 7, 2010. Many of the items in the exhibit have never been displayed outside of Mongolia.

In addition to wonderful artifacts such as weapons, armor, jewelry and saddles, the exhibit features live performances by Mongolian musicians.

The exhibit includes not only items from Genghis Khan's time, but also those from the reigns of his sons and grandsons. For example, Russia's Hermitage Museum lent objects from the Golden Horde which ruled Russia, plus parts of Central Asia and Eastern Europe.

Learn more about Genghis Khan, and read my interview with exhibit producer Don Lessem.

Photo by Sam Ose / Olai Skjaervoy on Flickr.com.

In Afghanistan, it is known as buzkashi and is the national sport. Turkic regions of Central Asia call it kok boru. Legend says that Genghis Khan's hordes played it to refine their horsemanship skills. At its roots, it is linked with another game that we consider quite posh today - polo.

So what is kok boru or buzkashi? It's a fast-paced game wherein two mounted teams battle for the headless body of a sheep, calf or goat. The object of the game is to deposit the animal within a goal ring marked on the ground.

Play can get pretty rough - the riders aren't supposed to lash one another with their riding whips, but it has been known to happen! Broken arms and legs are common, as well.

For more images, see the BBC photo gallery of kok boru players in Kyrgyzstan.

Photo by Paula Bronstein / Getty Images.