Why did the allies attack dardanelles?

Answer 1

Because the British had the fanciful, though strategically ingenious, idea of supplying Russia from the mediterranean rather than via the arctic or baltic sea routes. The problem being Turkey is in the way & the sea lane into the black sea would need to be clear of mines & shore defences. Had the attackers, having got ashore, got on with the invasion instead of defending the landing sites then the invasion might well have been a success. As it was it was a dismal, costly failure in which the lives of many Commonwealth soldiers were needlessly lost for no purpose whatever.

Answer 2

The allies wanted control of the dardanelles because it was the only waterway between the Black Sea and the Mediterranean Sea. Whoever controlled Dardanelles had a direct line to the Russian navy. The allied forces loss, but they had hoped if they won, they could persuade more countries to join their side.

Answer 3

To prevent Russia from getting control over it, because if they did they would have control over the Med and Black Sea. Which in fact would give them world power