Why Did the Twin Towers Collapse? 9/11 Explained

Why did the Twin Towers collapse on 9/11? The engineering answer — impact damage, fireproofing failure, and progressive collapse — explained clearly. On September 11, 2001, two hijacked Boeing 767s struck the World Trade Center’s Twin Towers. Within less than two hours, both 110-story skyscrapers were gone. Nearly 3,000 people lost their lives. But why did steel towers — designed with airplane impact in mind — actually fall? This video explains the official findings of the U.S. National Institute of Standards and Technology (NIST): ✅ Aircraft impact severed columns and stripped fireproofing ✅ Multi-floor fires weakened exposed structural steel ✅ Sagging floor trusses pulled exterior columns inward ✅ Upper sections dropped → progressive collapse KEY FACTS: • North Tower hit 8:46 a.m. (floors 93–99) — collapsed 10:28 a.m. (~102 min) • South Tower hit 9:03 a.m. (floors 77–85) — collapsed 9:59 a.m. (~56 min) • Fires reached ~1,000°C (1,800°F) — hot enough to weaken steel, not necessarily melt it • NIST found no corroborating evidence for controlled demolition This is a factual educational explainer based on the NIST World Trade Center investigation (NCSTAR 1). It is not a conspiracy video. We focus on structural engineering so viewers can understand what the official science says. SOURCES: • NIST WTC Towers Investigation: https://www.nist.gov/world-trade-center-investigation • NIST FAQs – WTC Towers: https://www.nist.gov/world-trade-center-investigation/study-faqs/wtc-towers-investigation • 9/11 Memorial & Museum: https://www.911memorial.org/ If this helped you understand 9/11 more clearly: 👍 Like the video 🔔 Subscribe for more 💬 Comment: Should Part 2 cover Building 7 in full? Never forget. September 11, 2001. Disclaimer: This video is for educational purposes #911 #twintowers #september11 0:00 The mystery of 9/11 0:30 Design of the Twin Towers 1:20 Impact and initial damage 2:41 The collapse sequence 4:25 Debunking common myths 5:10 World Trade Center 7 5:35 Human cost and legacy