Approx.
150,000 to 200,000 Allied soldiers landed on the shores of Normandy Beach--the first time the English channel had been crossed by an invading army since 1688--something like 25 miles across and not smooth sailing on any day. Around 100,000 made it alive into France.
It was kept absolutely top secret (no small feat) and it was HUGE. Just the black and white figures on the amount of soldiers, ammunition, and conveyances involved in the invasion is staggering!
As far as the turning point in the war and liberation of France, that's an aspect with which I'm not as familiar. But I'd say the turning point had a good deal to do with the morale of the people in the countries who were part of the Western Allied Forces...this was a daring offensive move, unprecedented and as yet, unequaled, I think.
Here is a good link:
http://www.pbs.org/wgbh/amex/dday/sfeature/sf_info.html
at PBS.org.
Have you seen the movie
'Saving Private Ryan'? If not, I recommend it, if just for the impact of the opening scene--although it is definitely graphic--overwhelming but very
real.
My dad was a sniper/scout--he hit the beach at Normandy on D-Day +1 (the day after the invasion). I can't imagine how he dealt with such an event.
Are you doing this for school?