Return of the Bedbug

What: The rise of bedbugs in New York City is related to the decline of DDT use.
When: 1950s to the present
Where: Everywhere

When Hogs Ruled

What: About 20,000 hogs—one for every five people—roamed the city in the first half of the 19th century. After the outbreak of cholera epidemics in the 1830s, the pigs were persecuted by the police and driven to other boroughs. It was later discovered that they were not to blame for the epidemics.
When: 1820
Where: Everywhere in Manhattan