What is “Sirat Bridge”?

Can you give some information about "Sirat Bridge" which is described as "thinner than a hair, sharper than a sword"?

Answer:

The Bridge of Sirat is described as the one being above the hell and thinner than a hair and sharper than a sword, over which all the people will cross in the hereafter.
While crossing over the Sirat, the people’s good deeds will be the vehicles carrying them. The speed of these vehicles will differ up to the level of people’s deeds. Some will pass like a lightning, some by flying, some by running, and some in the walking speed, some by crawling or creeping facedown. Kaynak: http://askaquestionto.us - What is “Sirat Bridge”?