What happened to fort ticonderoga, and why was it significant?

The Capture of Fort Ticonderoga occurred during the American Revolutionary War on May 10, 1775, when a small force of Green Mountain Boys led by Ethan Allen and Colonel Benedict Arnold overcame a small British garrison at the fort and looted the personal belongings of the garrison. Cannons and other armaments from the fort were later transported to Boston and used to fortify Dorchester Heights and break the standoff at the Siege of Boston.

After seizing Ticonderoga, a small detachment captured the nearby Fort Crown Point on May 11. Seven days later, Arnold and 50 men intrepidly raided Fort Saint-Jean on the Richelieu River in southern Quebec, seizing military supplies, cannons, and the largest military vessel on Lake Champlain.

Hope this helps :)

The answer is installation.