The tragedy at Boston’s Cocoanut Grove in 1942 is still the deadliest nightclub fire in history. The cause of the fire is still unknown; in its wake, advancements were made in fire safety and medical treatments for burn victims.
Research:

Robert Moses and the Shaping of New York, Part 2
42:12

Robert Moses and the Shaping of New York, Part 1
41:59

SYMHC Classics: Eradication of Smallpox
43:25