The Pudding Lane Spark refers to the small but pivotal incident at a bakery on Pudding Lane that ignited the catastrophic Great Fire of London in 1666. Originating from an unattended oven, the fire rapidly spread due to wooden structures and narrow streets, ultimately destroying 13,200 houses, 87 parish churches, and iconic landmarks, including St. Paul's Cathedral. This urban disaster rendered 70,000 citizens homeless and led to significant reforms in fire safety and urban planning in London.