( CNN ) The graffiti , written in a French chalk quarry and dating back almost 100 years , is plain and stark . `` HJ Leach . Merely a private . 13/7/16 . SA Australia , '' reads one inscription . `` HA Deanate , 148th Aero Squadron , USA . 150 Vermilyea Ave , New York City , '' another says . `` 9th Batt Australians , G. Fitzhenry , Paddington , Sydney , N.S.W. , 1916 July ; Alistair Ross , Lismore , July , '' reads a third . They were World War I soldiers , four of almost 2,000 , whose writings have recently been found underneath battlefields near Naours , France , about 120 miles north of Paris . Photographer Jeff Gusky , who has been chronicling details of the site , describes the inscriptions -- and the underground city in which they were found -- as `` breathtaking . '' `` This is a treasure trove , '' he said Monday night from his home in East Texas , where he works as an ER doctor . `` Even locally , no one realized what was there . '' Gusky , a National Geographic photographer , has chronicled the area in a portfolio he calls `` The Hidden World of WWI . '' The revelations of the underground city , which extends for miles in some directions , have come to light recently only because of a series of events , Gusky said . The underground city actually dates back centuries but was sealed up in the 18th century . It was rediscovered in the late 19th century . During World War I , soldiers would take refuge in the carved-out rooms and pathways . The front was sometimes mere miles away ; the Battle of the Somme , one of the bloodiest in world history , was fought nearby in 1916 . The land was privately owned for many years and generally off-limits to outsiders , said Gusky , but it changed hands in 2013 . The rights to operate it were purchased by a consortium of villages that wanted to promote awareness of the area 's history , he said . Researching the city is a painstaking task . For one thing , it 's dark , so observers generally have n't realized what 's in there until they 've gone exploring . Moreover , the maze-like extensiveness of the site has made discovery a slow process . `` They go on and on and on . They 're so elaborate in some places , there are maps carved into stone so the soldiers would n't get lost , '' he said . The graffiti looks like it was written yesterday , he added . Gusky has noted 1,821 names . About 40 % are Australian , with most of the others identified as British . Fifty-five are Americans , and 662 have yet to be traced . For Gusky , the graffiti provides a human connection with men who lived a century ago . In many cases , they just wanted to be remembered , he said . `` Someone could be in this place one day and the next fighting at the front , '' he said . Leach , `` merely a private , '' was killed a month later in battle , Gusky observed . `` It could very well have been the last time he recorded his name as a living , breathing human being , '' he said . 7 things you did n't know about the man who started WWI .
World War I graffiti is discovered in an underground quarry . The writings are generally plain , with listings of names and places . Photographer : Graffiti a human connection to the past .