The holder of half a dozen world records will walk across the Grand Canyon on a steel cable with nothing but the Little Colorado River 1,500 feet below on June 23. With no tethers or safety nets, the walk will be the highest tightrope attempt ever for the 34-year-old, at a height taller than the Empire State Building. Last year, Wallenda, a seventh-generation member of the “Flying Wallendas” family of acrobats, became the only person to walk a wire over the brink of Niagara Falls. Photo: Nik Wallenda walks across a tightrope 200 feet above U.S. 41 on January 29, 2013 in Sarasota, Florida. (Photo by Tim Boyles)

Despite the high winds and fright temperatures, about 1/2 dozen brave members of the Coney Island Polar Bear Club took a dip in the Atlantic Ocean at March 14, 2017, just of Stillwell avenue in Coney Island beach in Brooklyn NYC. (Photo by Paul Martinka)

In this photo taken on March 16, 2019, 13-year-old Reymark Cavesirano collects left over herring onboard a fishing boat anchored at the mouth of Manila Bay off Navotas City in suburban Manila. Cavesirano, a grade five student, paddles to the anchored fishing boats and helps crew clean their nets, and in exchange collects leftover herring still tangled in the nets. Across the Philippines, there are 5 million child labourers, aged between five and 17, many of them working in dangerous conditions. About 22 million people – a fifth of the population – live below the national poverty line. (Photo by Ted Aljibe/AFP Photo)

“Eye of a toad”. Animal Portraits, Łukasz Bożycki, Poland. Early spring sees a pond near Łukasz’s home city of Warsaw, Poland, full of mating frogs and a few toads. On this March day, Łukasz shared the pond with them for an evening, sitting in the icy water in his chest-high waders, keeping as still as possible, despite the numbing cold, so that the amphibians could get used to him. “I wanted to find a fresh way of portraying the amphibians”, he says, “at water level”. Using a telephoto lens, he focused on one lone toad and waited for the sun to dip almost below the horizon before pressing the shutter, using flash to bring out the details in the shadow. His prize was “the glorious pool of sunset colour” and fiery glow of the toad’s eye. Nikon D80 + 70-300mm f4.5-5.6 lens + extension tube; 1/125 sec at f9 (-2.3 e/v); ISO 100; built-in flash. (Photo by Łukasz Bożycki)

With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

Garbage pickers collect ride on donkey cart while looking for recyclable materials at a rubbish dump in the outskirts of Baghdad, Iraq, August 23, 2016. Despite its huge untapped oil and gas reserves and steadily rising oil output and revenue, 23 percent of the population live below the poverty line, according to the Ministry of Planning. (Photo by Khalid al Mousily/Reuters)