A Christmas tree stands in Juan Pablo II square in Managua, Nicaragua, December 14, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Oswaldo RivasPICTURE 23 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES OSWALDO RIVAS (REUTERS)A Christmas tree made of 121 old wooden-framed, coloured windows, constructed by local carpentry students is seen in Rakvere, Estonia, November 29, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Ints Kalnins PICTURE 15 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES INTS KALNINS (REUTERS)An illuminated Christmas tree is displayed on central Syntagma square as the parliament building is seen in the background in Athens, Greece, December 4, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Alkis KonstantinidisPICTURE 21 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES ALKIS KONSTANTINIDIS (REUTERS)A Christmas tree stands in the Park Simon Bolivar in Bogota, Colombia, December 7, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/John Vizcaino PICTURE 25 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES JOHN VIZCAINO (REUTERS)Holiday lights shine on the 83rd Rockefeller Center Christmas tree, at Rockefeller Center in the Manhattan borough of New York, United States, December 2, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Lucas JacksonPICTURE 7 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES LUCAS JACKSON (REUTERS)Cars drive on a street illuminated by Christmas lights in Tbilisi, Georgia, December 14, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/David MdzinarishviliPICTURE 12 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES DAVID MDZINARISHVILI (REUTERS)People visit Christmas festivities amongst Supertrees structures at the Gardens by the Bay in Singapore, December 14, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Edgar SuPICTURE 5 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES EDGAR SU (REUTERS)A Christmas tree is seen at a roundabout in Victoria Island district in Lagos, Nigeria, December 9, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Akintunde AkinleyePICTURE 17 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES AKINTUNDE AKINLEYE (REUTERS)A Christmas tree stands in Byblos, north of Beirut, Lebanon, November 25, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Mohamed AzakirPICTURE 10 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES MOHAMED AZAKIR (REUTERS)Christmas decorations are seen in front of the Cathedral of Lima, in downtown Lima, Peru, December 7, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Mariana BazoPICTURE 24 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES MARIANA BAZO (REUTERS)Christmas tree is seen in front of the Tokyo Metropolitan Government Building (2nd R) at Tokyo's Shinjuku business district, Japan, December 6, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Yuya ShinoPICTURE 3 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES YUYA SHINO (REUTERS)Young women walk past a Christmas tree in central Moscow, Russia, December 14, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Maxim Shemetov PICTURE 14 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES MAXIM SHEMETOV (REUTERS)A Christmas tree is pictured at Rodrigo de Freitas Lagoon in Rio de Janeiro, Brazil, December 15, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Sergio MoraesPICTURE 22 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES SERGIO MORAES (REUTERS)The U.S. Capitol Christmas Tree stands after the lighting ceremony on Capitol Hill in Washington, United States, December 2, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song "O Tannenbaum" is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. REUTERS/Joshua RobertsPICTURE 20 OF 28 - SEARCH "GLOBAL TREES" FOR ALL IMAGES JOSHUA ROBERTS (REUTERS)