US President Barack Obama has renewed his call to reduce the world's nuclear stockpiles during a speech in front of Berlin's iconic Brandenburg Gate.<br />Obama pledged on Wednesday to reduce the number of nuclear weapons held by Russia and the US by one-third during a speech which used the theme "peace through justice".<br />He also called for a global reduction in the manufacturing of materials used in the construction of nuclear weapons.<br />The speech also included pledges over tackling climate change, which the president called "the global threat of our time" and unemployment.<br />Al Jazeera's Nick Spicer reports from Berlin.
