Burj Khalija plunged into darkness as UAE celebrate Earth Hour The United Arab Emirates joined the global movement for Earth Hour on Saturday to raise awareness on the effects of climate change, plunging Burj Khalifa, Dubai's biggest landmark and the world's tallest building, into darkness to mark the occasion. Millions are taking part around the world in the annual event organised by conservation group WWF, with hundreds of other well-known sights also set to plunge into darkness. IMAGES AND SOUNDBITES