The Global Impact Challenge supports British non-profits using tech to tackle the world's toughest problems. The 10 finalists are in, help decide who wins.Project:Amnesty International will work with activists and partners to develop a mobile alert system that enables individuals to immediately transmit a message to their trusted networks in an emergency.Impact:Human rights activists are under threat around the world. Too often they are subject to violence, torture, or disappearance.Amnesty International plans to launch a mobile alert system, and train and support activist networks to use it. The system will be scaled globally, aiming to reach between 75,000-100,000 people over 2.5 years. This rapid response tool will revolutionise the way activists work and therefore how human rights are protected around the world.Get involved:Cast your vote by the 31st May on https://globalimpactchallenge.withgoogle.com/ for the £500,000 fan favourite Global Impact Award.