Remnants of London’s past can be found etched and faded on brick walls, only to be seen by those who know where to look. They are called ghost signs, and hundreds of them exist in the English capital.

But with the development of more than 200 new skyscrapers, most of these signs may disappear forever.

In the early 1900s, businesses would hand-paint advertisements and specials on the side of brick buildings. Thanks to years of poor weather, construction, and general erosion over time, these advertisements have slowly faded away.

Sam Roberts is the founder of Ghostsigns, a research-and-publishing initiative that photographs, archives, and promotes awareness of the fading hand-painted signs. He also gives two-hour walking tours to anyone interested in learning more about the history of the signs.

Roberts says that most people don’t notice these special pieces of London’s history because they don’t know where to look.

“Normally you're focused on eye level, on the ground,” he said to CTV News. “But with these things you need to look up.”

Each sign was created by a skilled craftsman called a signwriter or a “walldog.” They either hand-painted the sign or used a spike wheel to scratch designs into the brick.

This meant a lot of work. One advertisement, a 90-year-old Black Cat cigarette ad located on an old tobacco factory, is even bigger than a modern-day billboard.

Roberts wants to stress the importance of maintaining these commercial heritage sites and the work that went into their creation so long ago. His worry is that if people aren’t aware of them, they will disappear entirely.

“The property developers, their impact is much more sudden,” Roberts said. “(They are) either demolishing a building or completely painting over the signage.”

With a report by Daniele Hamamdjian in London, England