When it starts
On April 25th, 1915, Russia's Grand Duke Nicholas appealed to Britain's caucus for aid in the launching a Turkish invasion. The Gallipoli campaign started in Turkey early in 1915 after the British agreed to help. The British and French ships were trying to take over the Dardanelles Strait but they were unsuccessful. Then from February to March 1915, they continued the attack on land. The allied powers were debating whether to go on the offence in another region of the conflict rather that continuing with the attacks in Gallipoli.
Central powers responed
By November 1916, the Ottoman Empire had entered World War 1on the Central Powers side, Germany and Austria-Hungary. In response, the allies sent a naval expedition to the Aegean Sea. Dardanelles Strait is a narrow passage connecting the Aegean Sea to the Sea of Marmara in Northwest Turkey. If they were successful they would capture the strait and meet up with the Russians in the Black Sea and work together to knock Turkey out of the war. This was spearheaded by the first lord of the British Admiralty, Winston Churchill (over the strong opposition of the First Sea Lord Admiral John Fisher, Head of the British Navy). The naval attack on the Dardanelles began with a long-rang bombardment by British and French battleships. On February 19, 1915. Turkish forces abandoned their outer forts but met the approaching Allied Minesweepers with heavy fire stalling the advance. Turkey didn't surrender, they abandoned their country. That's when the battle ended, it was January 9th, 1916. The campaign was believed to kill over 200 000 Turkish men. Out of all the countries that where in the campaign 400 000 men died from an illness.