Template:On This Day (nonfiction)/April 29
1667: Physician, satirist, and polymath John Arbuthnot born. He will invent the figure of John Bull.
1854: Mathematician, physicist, and engineer Henri Poincaré born. He will make many original fundamental contributions to pure and applied mathematics, mathematical physics, and celestial mechanics.
1893: Chemist and astronomer Harold Urey born. Urey's pioneering work on isotopes will earn him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium; he will also play a significant role in the development of the atom bomb, and contribute to theories on the development of organic life from non-living matter.
1951: Philosopher and academic Ludwig Wittgenstein dies. Wittgenstein contributed to logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.
1974: Watergate scandal: United States President Richard Nixon announces the release of edited transcripts of White House tape recordings relating to the scandal.
1986: Chernobyl disaster: American and European spy satellites capture the ruins of the 4th Reactor at the Chernobyl Power Plant.
2008: Chemist and academic Albert Hoffman dies. Hoffman is famous for discovering LSD, which he called his "problem child".