Subject: Why are car engines commonly placed in the front of the vehicle?

I am trying to figure out why automotive manufacturers chose to place the 
engine in the front of a vehicle and not the rear. I believe by placing the 
engine in the front there is greater amounts of structural stress placed on the 
frame of the vehicle. Also, why do most exotic cars have rear or mid engine 
vehicles? Wouldn't that show that these exotic manufacturers realized (perhaps) 
that engines in the rear are more efficient in terms of performance and 
strength. I suppose a V12 engine in a Lamborghini would be better off than in a 
station wagon in terms of structural stress given that the Lamborghini has 
better than average materials. Thanks.

Re: Why are car engines commonly placed in the front of the vehicle?