Why did the Concorde require a droop nose and how did it work?

As seen in the picture below, Concorde used to have a droop nose which would be deployed during takeoff/landing and would be retracted to the normal position while in cruise (do reduce drag).

Concorde with a droop Nose deployed

Concorde in normal configuration

According to the wiki page on Concorde, this Droop Nose was added in the later versions of Concorde when the authorities raised questions about the restricted view which was available to pilots during landing/take off at very high angles of attack (which was required for the Concorde).

1. What are the other possible solutions which could have been employed instead of the droop nose to tackle to the restricted view from the cockpit?

2. Why did Concorde had to land and take off at higher than normal angle of attacks?

3. How did the Droop nose actually work? (Which mechanism was used to deploy and retract it)

• You may look at those videos to see it in action. – Manu H Jul 13 '15 at 10:30
• What are the other possible solutions bordering on too broad, but let's see what the others say. – Federico Jul 13 '15 at 10:53