In preparation for the Dubai Duty Free Men's Open, Andre Agassi and Roger Federer of Switzerland, couldn't resist the temptation to have a friendly “hit” on the world's most unique tennis court, the Helipad of the Burj Al Arab, the world's most luxurious hotel. Standing 321 metres high on a man made island, the majestic Burj Al Arab is without doubt the most recognizable hotel in the world. The hotel's helipad, which is situated 211 metres high covers a surface area of 415 square metres. The pictures were taken on February 22, 2005, in Dubai, United Arab Emirates. (Photo by Getty Images for Dubai Duty Free)

Centenarian Sikh runner Fauja Singh poses for pictures after being the first person to officially enter for next year's Edinburgh Marathon on September 1, 2011 in Edinburgh, Scotland. A world record holder, aged 100, Fajua Singh has run seven marathons, all after his 89th birthday. He officially opened the entry process by signing up for his last ever 26 mile event in Edinburgh. (Photo by Jeff J Mitchell/Getty Images)

Photographer, Baron DaParre takes a picture of young model Danette Vega below an effigy dressed as a Wall Street banker hanging from a telephone wire on October 28, 2011 in Miami, Florida. As protests inspired by the Occupy Wall Street protesters continue around the country an artist known as Above, created the installation which hangs above a mural that reads “Give a Wall St. banker enough rope and he will hang himself”. (Photo by Joe Raedle/Getty Images)

Penguins majestically march on sand before heading out for a morning swim. Wildlife photographer Wim van den Heever, 45, visited the Falkland Islands this year to shoot pictures and scout the area for future tours. Wim’s breathtaking images show a small group of king penguins before they head out to sea at sunrise. Here: King Penguins marching during sunrise, Falkland Islands. (Photo by Wim van den Heever/Caters News)

These images capture the intricate details of minuscule snowflakes, moments before they melt. The shots were taken by Don Komarechka, 31, who has had a lifelong fascination with all things macro – especially snowflakes. The professional photographer says people often don’t believe that his pictures are real because they’re so perfect. (Photo by Don Komarechka/Caters News Agency)

A man carries his wife on his back as they make their way with their luggage along a flooded tunnel to catch their train, after heavy rainfall hit Jinhua, Zhejiang province, China, July 21, 2015. (Photo by Reuters/China Daily)

A picture composed by the French street artist JR is plastered to a wall under a highway as part of a community project called “Through A Mother's Eyes”, which involves members of the economically distressed neighborhood of Hunts Point in images taken by and of themselves on June 30, 2011 in New York City. JR, a recent TED prize winner, has staged similar projects around the world that look to transform high crime and impoverished neighborhoods into spaces for street art combined with the celebration of community. (Photo by Spencer Platt/Getty Images)

Macro or Micro? Scientists’ pictures baffle our sense of scale. It began when Stephen Young, a geography professor at Salem State University in Massachusetts, tricked his biologist colleague Paul Kelly into thinking a satellite image was one of his electron microscope scans. Can you guess whether they are close-up or very far away? (Photo by Paul Kelly)