A concept illustration of the world's first forest in the sky, the Bosco Verticale green twin towers currently under construction in Milan, Italy. Towering over the city skyline the world's first forest in the sky will be a sight to behold. With tree equal to one hectare of forest spanning 27 floors these 365 and 260 foot emerald twin towers will be home to an astonishing 730 trees, 5,000 shrubs and 11,000 ground cover plants. (Photo by Boeri Studio)

Construction cranes stand on the Unstrut Valley high-speed railway bridge on March 19, 2012 near Karsdorf, Germany. The Unstrut bridge, which is 2,668m long (about 1.6 miles), is among 38 bridges and 26 tunnels German state rail carrier Deutsche Bahn is building along a new ICE high-speed railroad connection between Nuremberg, Erfurt, Halle, Leipzig and Berlin in a multi-billion Euro project across eastern Germany called the German Unity Transportation Project (Verkehrsprojekt der Deutschen Einheit). (Photo by Sean Gallup/Getty Images)

Artists perform during the opening show directed by German director Volker Hesse, on the opening day of the Gotthard rail tunnel, at the fairground Rynaecht at the northern portal in Erstfeld, Switzerland, Wednesday, June 1, 2016. The construction of the 57 kilometer long tunnel began in 1999, the breakthrough was in 2010. After the official opening on June 1, the commercial operation will start in December 2016. (Photo by Ruben Sprich\Pool Photo via AP Photo)

Wind turbines stand in the Baltic 1 offshore wind farm on April 29, 2011 in the Baltic Sea near Zingst, Germany. Baltic 1, a project of German energy utility EnBW that includes 21 turbines rated at 2.3 megawatts each, will be Germany's first commercial offshore wind farm once it officially begins operation on May 2. Germany has thus far lagged in offshore wind farm construction when compared to neighbors like Great Britain and Denmark, though German Chancellor Angela Merkel has vowed to invest heavily into offshore wind farms as part of an overall policy to encourage renewable energy production. (Photo by Joern Pollex/Getty Images)

Kashir Mir, 34, poses for a photograph at his workplace, Juliet Wig Shop, in the London constituency of Brent Central, Britain, April 13, 2015. Mir, who was born in Pakistan, said: “I will vote but it's a secret. I also hope they can manage immigration better as I have been stopped and interviewed for hours returning from Pakistan. I'm an honest man, working here and paying my tax”. Brent, a northwest London neighbourhood that's home to Wembley football stadium, is among the most ethnically diverse areas in the United Kingdom. As the country approaches a closely fought election on May 7, Reuters photographer Eddie Keogh visited shopkeepers to get their views on the poll. (Photo by Eddie Keogh/Reuters)

A picture made available 26 April 2016 shows a tiger playing in the water with a trainer nicknamed “Super Tiger Man” at the Tiger Temple in Kanchanaburi province, Thailand, 24 April 2016. The site known in Thai as “Wat Pa Luangta Maha Bua Yannasampanno” has been the focus of a dispute with the Department of National Parks, Wildlife and Plant Conservation (DNP) after the DNP asked in 2015 that the temple hands over its 147 tigers since it was not licensed to keep them. The temple has requested for a zoo license according to its managing director. (Photo by Diego Azubel/EPA)

Pregnant Tibetan antelopes move across the Qinghai-Tibet highway in Hoh Xil, northwest China's Qinghai Province, May 29, 2023. A growing number of pregnant Tibetan antelopes are migrating to the heart of northwest China's Hoh Xil National Nature Reserve to give birth, according to the reserve's management office. Every year, tens of thousands of pregnant Tibetan antelopes start their migration to Hoh Xil in around May to give birth and leave with their offspring in late July. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

These photographs are the work of urban explorer Dr Bradley Garrett who made headlines back in 2012 when he posted a series of snaps from the top of The Shard skyscraper while it was still under construction. Garrett, now a researcher at the University of Oxford, took these shots during his time with the London Consolidation Crew (LCC), a loose collection of urban explorers based in the English capital. Photo: Bradley Garrett stands on the edge of the Ritz-Carlton Chicago as lightning strikes in the distance in Chicago, US. (Photo by Bradley L. Garrett/Barcroft Media)