Gianina Rojas steps outside her house in Lima, Peru. She sees two golf courses, three slums, and a crumbling Inca pyramid.

Wait—a pyramid? Most of us would be shocked to see a pyramid from our front door! But Ms. Rojas is used to it. “Lima is full of places like this,” she says.

The Inca people were natives of South America. Their empire ended almost 500 years ago when the Spanish took over. But even after all this time, you can see about 46,000 historical sites from before the Spanish arrived. Around 400 of the sites are in Lima. No other city in South America has that many haucas. (Huaca is a Native American word for “sacred place.”) As a kid, Ms. Rojas hunted for Inca treasure. She stowed away pieces of ancient ceramic pots, fabric, and even human bones!

All those ruins may make for a great treasure hunt. But they also make it hard to find homes. The population in Peru keeps growing. People search for places to live. They struggle to locate huaca-free spots. They build roads, schools, stadiums, and neighborhoods—right beside historic sites. They dig tunnels under an adobe palace at a 900-year-old cemetery. Highway traffic barrels through. Archaeologists worry. After all this building, how many historical sites will be left in Lima?

Protecting historical artifacts takes a lot of money. And it must be balanced with meeting the needs of the people today. The Peruvian government currently spends enough to safeguard just one percent of its many historic sites. Hundreds of ruins are abandoned. People dump trash in them. Some archaeologists and officials want to make a change. They want Peruvian people to take care of this history—before it disappears.