A photography project reminds us that soldiers surrendered and prisoners marched on the same streets we walk along every day.

"It is a bit like painting with history," says Jo Hedwig Teeuwisse.

She got the idea for her project, "Ghost of History," a few years ago when she found some old negatives at a flea market in Amsterdam, where she lives. "I was very curious about these mysterious photos and wanted to find out who took them and where. So I started to walk around Amsterdam and made photos in the same spot where the old photos were made and combined them on the computer." She has been slowly building her collection online since 2007. At first the task was easy -- since she lives in Amsterdam she recognized the locations herself. But as her project has expanded to include other sites of World War II destruction, she's found that she can crowdsource the answers. "Sometimes I had to post a photo on the internet and ask people if they knew where it was. ... Now I also put a photo on facebook and ask people if they know where it is and if they can send me 'now' photos. This way I can also make the pictures about subjects in other countries far from where I live." Websites such as PhotosNormandie and Tom Timmermans' Battle Detective also let her use some of the photos they had located.

The process for making the images is pretty simple. "You put the old photo on top of the new photo, you make them line up and then you start removing parts," she says. "It is not about how you do it, because the computer does most of the work and it is not that hard to do. But it is about deciding what you want to show, what you want to remove and where you want the viewer to look at. If you make the right choice the combination tells a story, it makes people think." Here are the two photos she's used to make the image above: