Filippo Negroli (ca. 1510–1579) was an armourer from Milan. He was renowned as being extremely skilled, and may be considered the most famous armourer of all time. Working together with his younger brothers Giovan Battista (ca. 1511-1591) and Francesco (ca. 1522-1600) in the Negroli family workshop headed by their father Gian Giacomo Negroli (ca. 1463-1543), Filippo was specialized in repoussé of armour, whereas his brother Francesco was renowned for his damascening skills.

Founded in 1989, the Icehotel in Swedish Lapland is built from the snow up each year, using ice from the local river. The rooms are designed by international artists and this year feature spacemen and an ice queen. The hotel has 35 suites, featuring ice carvings designed by 36 different artists from 17 countries. (Photo by Asaf Kliger/IceHotel/The Guardian)

Ender Moreno looks for gold at La Culebra gold mine in El Callao, Bolivar state, southeastern Venezuela on March 1, 2017. Although life in the mines of eastern Venezuela is hard and dangerous, tens of thousands from all over the country head for the mines daily in overcrowded trucks, pushed by the rise in gold prices and by the severe economic crisis affecting the country, aggravated recently by the drop in oil prices. (Photo by Juan Barreto/AFP Photo)

A stork-billed kingfisher (Pelargopsis capensis) is seen perched on a tree during monsoon rain on July 25, 2016 in Bintan, Indonesia. The stork-billed kingfisher is a tree species which is widely but sparsely distributed in the tropical Indian subcontinent and Southeast Asia, from India to Indonesia. This kingfisher is resident throughout its range. It is very large, measuring 35 to 38 cm (14 to 15 in) in length. The adult has a green back, blue wings and tail, and grey head. (Photo by Sijori Images/Barcroft Images)

An Israeli soldier prays in front of a tank at a military staging area near the border with the Gaza Strip, in this July 24, 2014 file photo. Israel's long-running struggle to balance modern standards with Jewish tradition has come to a head in the military, where new orders curtailing beards among soldiers have met protests from some rabbis. (Photo by Nir Elias/Reuters)

Beneath the Swedish capital lies an intricate web of underground train lines. More than 90 of the 100 stations in the 110km tunnel system, sometimes referred to as “the world’s longest art gallery”, have been decorated with paintings, installations, mosaics and sculptures by 150 artists since the 1950s. After spending a couple of weeks exploring arctic Norway and Sweden, London-based travel photographer Conor MacNeill headed underground to capture images of the metro stations. Here: A rainbow arcs over a girl on the platform of Stadion station. (Photo by Conor MacNeill/The Observer)

Wildlife photographer Danté Fenolio has headed into areas untouched by sunlight – deep seas, caves and underground – and found creatures that are exploding with colour. Here: The golden harlequin toad has vanished from the wild, and only a small number live on in captivity. A fungus caused them, and many other amphibians, to die out in their home in Central America. (Photo by Danté Fenolio/The Guardian/Johns Hopkins University Press)

Stones collected and categorised by shape (fish) are seen at the home workshop of Luigi Lineri in Zevio, near Verona, Italy, June 10, 2016. Luigi Lineri's home workshop is covered in stones – tens of thousands of them. They resemble animal heads, human faces and other forms, and the artist and poet believes may have been shaped by prehistoric humans. (Photo by Alessandro Bianchi/Reuters)