The 1906 earthquake, one of the worst natural disasters in U.S. history, occurred on April 18, causing an estimated 3,000 deaths and leaving 200,000 homeless. The breakdown of basic infrastructure led to a citywide catastrophe, with buildings collapsing, gas lines ruptured, and water mains snapped. The earthquake also revealed the nature of earthquakes, leading to a breakthrough in how to predict them. The city has developed a specialized emergency firefighting water system and developed the Neighborhood Emergency Response Team program following the 1989 Loma Prieta earthquake. However, experts warn that a major earthquake could still disrupt power, water, transportation, and online communications all at once. Despite these improvements, the public's level of preparedness remains a critical point.