Which allied force failed to capture the ridge in 1915?

In 1915, the Allied forces that failed to capture the ridge were primarily the British and ANZAC (Australian and New Zealand Army Corps) troops during the Gallipoli Campaign. The campaign aimed to secure a sea route to Russia and capture the Dardanelles but faced strong Ottoman resistance and challenging terrain. The failure to capture key positions, including the heights of Gallipoli, ultimately led to significant Allied losses and a withdrawal from the peninsula by early 1916.