A woman takes a photograph of a section of Hadrian's Wall at Housesteads Roman Fort near Hexham, northern England, on January 19, 2022. - This year marks the 1900 anniversary of the start of the construction of Hadrian's Wall, which took 6 years to complete and was built to guard the northern frontier of the Roman Empire in 122 AD. The wall ran for 73 miles from the Solway Firth to Wallsend on the River Tyne and is now designated a UNESCO World Heritage Site. The wall featured over 80 milecastles or forts, two observation towers and 17 larger forts. After the Romans left Britain in the early 5th century, some 300 years after the wall was constructed, large sections of the wall fell into decay and were recycled into local buildings and houses. (Photo by OLI SCARFF / AFP)