World leaders have remembered the twentieth anniversary of the fall of the Berlin Wall. German Chancellor, Angela Merkel, was joined by Russia's Dmitry Medvedev and France's Nicolas Sarkozy at the Brandenburg Gate. In a video address, Barack Obama told them that the Berliners had rebuked tyranny on November 9, 1989. Some 136 people are thought to have been killed whilst trying to escape through the Wall. Merkel, who grew up in East Germany, presided over the celebratory events, which were attended by tens of thousands of people.

Thomas Drummond made the first practical use of limelight while surveying in Ireland to enable work through misty days and night. He created an intense light from a lump of lime (calcium oxide) heated to incandescent by an oxygenated alcohol flame in front of a reflector. The haze over Lough Neagh obscured the view between Slieve Snaght, in Donegal, and Divis Mountain 66 miles away near Belfast, but the light penetrated it. He attempted to adapt it for lighthouses, but found operation too costly. The bright light given off by heated metal oxides was first investigated in the 1820s by Goldsworthy Gurney who created the oxyhydrogen blowpipe. Limelight was also used not only in theatres, but even for microscope illumination.