Johan de Witt (1625)

De Witt was a Dutch statesman who played a vital role in the three successive Dutch Wars. He helped end the first in 1654, but the English Restoration was considered a threat to Dutch interests and the conflict was renewed in 1665. He was largely responsible for securing for the Dutch the favorable terms of the treaty that ended the second of the wars and helped form the Triple Alliance against Louis XIV, who nevertheless invaded Holland in 1672. Why was de Witt lynched shortly thereafter? Discuss

The Water Clock

The clepsydra, or water clock, is an ancient timekeeper that operates by measuring the regulated flow of liquid into or out of a vessel. It is believed to have been used in Egypt as early as 2,000 BCE, making it one of the earliest known time-measurement devices. Early water clocks were calibrated with a sundial, and they remained the most accurate timekeeping devices until the invention of the pendulum clock in the 17th century. When did knowing the time become important to the common man? Discuss

El Grito de Lares: The Lares Uprising (1868)

The Lares rebellion of 1868 was the most notable uprising in a series of failed Puerto Rican rebellions against Spanish rule that began in the 1820s. Best known as El Grito de Lares, or The Cry of Lares, the revolt took place in the town of Lares, where rebels briefly declared independence. Though the rebellion was brutally and swiftly suppressed, Lares has come to be known as the birthplace of Puerto Rican nationalism. Who was declared the republic’s first president during the rebellion? Discuss

Typhoid Mary (1869)

Mary Mallon was the first person in the US to be identified as a healthy carrier of typhoid fever. In 1904, a typhoid epidemic was traced to homes where she had been a cook. She fled but was located by authorities and forcibly quarantined for several years. In 1910, she was released on the condition that she not take another food-handling job. Discovered cooking again in 1914, she was quarantined for life. Though she herself never had the disease, she infected about 50 people. How many died? Discuss

Prometheus, The Tree

In 1964, Prometheus, a Great Basin Bristlecone Pine, was the oldest known non-clonal organism on Earth. That year, a graduate student cut down the 5,000- year-old tree to examine its ring growth patterns and derive information about the climate. It is unclear who suggested that Prometheus be cut down, why the action was deemed necessary, and whether its impact was fully understood at the time. Methuselah is currently the oldest known living tree. How old is it? Discuss

The Vela Incident (1979)

In the 1960s, the US launched a group of satellites to monitor international compliance with a treaty prohibiting all tests of nuclear weapons except those conducted underground. In 1979, one of the satellites detected an unidentified double flash characteristic of an atmospheric nuclear explosion. The data were initially interpreted as evidence of a South African nuclear test, but experts later determined that the flash was likely not nuclear in origin and may have instead been caused by what? Discuss