The 1908 Tunguska Event, thought to have been caused by an asteroid about 50 meters in diameter, flattened 2,150 square kilometers of forest, an area equivalent to that of Tokyo.
Notes on verification
Corroborated by NASA, ESA, and Britannica regarding event date, affected forest area, and estimated impactor size; Tokyo comparison holds when using the metropolis/prefecture area (~2,194 sq km). [cascade flags: aggregator_dropped_primary_exists,wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.925 clusters=2 claim_tier=notable | framework convergence=partial on Historical tree-fall survey data from Tunguska site expeditions (upstreams: Soviet/Russian scientific expeditions to Tunguska site (Kulik expeditions and later surveys), NASA impact modeling) — publishers independent, evidence may not be | kind=empirical eligibility=high]
Sources
- July 5: the day the world was due to end – Cosmos (seed:space_and_astronomy)
- https://www.nasa.gov/history/the-tunguska-event/ (corroboration)
- https://www.metro.tokyo.lg.jp/english/about/history/index.html (corroboration)