Some of Britain 's most iconic landmarks were plunged into darkness to raise awareness of climate change . Lights at Big Ben , the Eiffel Tower , Tower Bridge and Old Trafford switched off for Earth Hour at 8.30pm . 700 monuments worldwide went dark , including Buckingham Palace in Paris and Brandenburg Gate in Berlin .
Some of Britain 's most iconic landmarks were plunged into darkness to raise awareness of climate change . Lights at Big Ben , Buckingham Palace , Tower Bridge and Old Trafford switched off for Earth Hour at 8.30pm . 700 monuments worldwide went dark , including the Eiffel Tower in Paris and Brandenburg Gate in Berlin .