The site of a former mass grave is seen in Snagovo near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Budak near Srebrenica, Bosnia June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic

The site of a former mass grave is seen in Kamenica near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Crni Vrh near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Kamenica near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Crni Vrh near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Snagovo near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Crni Vrh near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Pilice near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic 

The site of a former mass grave is seen in Kamenica near Zvornik, June 24, 2015. On July 11, 1995, towards the end of the Bosnian War, Bosnian Serb forces swept into a U.N.-designated "safe haven", from where they took 8,000 Muslim men and boys to be executed in the days that followed, dumping their bodies into pits in the surrounding forests. To mark the 20th anniversary of the massacre, Reuters photographer Dado Ruvic identified historic images of the mass graves from the Reuters archive and returned to the locations to photograph the sites today. REUTERS/Dado Ruvic