Here is a concise summary of the text:
**The Daring Escape from Alcatraz**
* In 1962, three inmates - Frank Morris and brothers John and Clarence Anglin - escaped from Alcatraz, the supposedly escape-proof prison island in San Francisco Bay.
* The mastermind, Frank Morris, had a history of 11 previous escapes and an IQ of 133.
* The trio used homemade tools to dig through their cell walls, created fake heads to deceive guards, and built a raft from stolen raincoats to sail to freedom.
* Despite an extensive search, no bodies were found, and the FBI initially concluded they likely died. However:
* Over 100 indirect evidence points suggest they may have survived, including:
+ Footprints on Angel Island
+ A stolen car report
+ A photograph (with 99.7% facial recognition match) of the Anglin brothers in Brazil, 13 years later
+ A letter (authenticity disputed) from John Anglin in 2013 claiming they survived
* The escape led to Alcatraz's closure in 1963 due to high maintenance costs and a tarnished reputation.
* Today, Alcatraz is a National Historic Landmark and a popular museum, with the escape inspiring numerous documentaries, films, books, and games.
Here are the key facts extracted from the text, numbered and in short sentences:
**Alcatraz Prison**
1. Alcatraz Prison was located on an island in San Francisco Bay, surrounded by icy water.
2. The prison was known for its strong security features, including steel bars, guard towers, and high fences with barbed wire.
3. Alcatraz was nicknamed "The Rock" and "The Prison of Prisons".
4. The prison operated for 29 years, from the early 20th century to its closure.
**The Escape**
5. On June 11, 1962, three prisoners, Frank Morris and brothers John and Clarence Anglin, escaped from Alcatraz.
6. The fourth conspirator, Allen West, was unable to escape due to a malfunction in his homemade hole.
7. The escapees used fake heads, made from wire, plaster, and paint, to deceive guards during the evening count.
8. They escaped through a ventilation hole, climbed down a chimney, and overcame a barbed-wire fence to reach the water.
**The Escapees**
9. Frank Morris, 33, was the alleged mastermind, with 11 previous escapes and a high IQ (133).
10. John and Clarence Anglin were serving sentences for bank robbery and escaping from another prison.
11. Allen West, the fourth conspirator, was a car thief who had also attempted to escape previously.
**Investigation and Aftermath**
12. The escape was discovered the next morning, during the rise.
13. An extensive search by the FBI, police, military, and coast guards yielded no immediate results.
14. Investigators found several pieces of evidence, including a homemade paddle, a rubberized bag, and a deflated life jacket.
15. The FBI initially concluded that the escape attempt had failed and the prisoners were likely dead.
16. In 2013, the FBI received a letter allegedly from John Anglin, claiming all three escapees survived.
**Legacy**
17. Alcatraz was closed a year after the escape, due to high maintenance and operational costs.
18. The island is now a National Historic Landmark, with the prison buildings converted into a museum.
19. Over 1.5 million people visit the museum annually.
20. The escape has inspired numerous documentaries, films, books, and computer games.