According to the World Wildlife Fund, nearly half of World Heritage sites are being threatened by industrial activity.
The United Nations awards the World Heritage site designation to locales that demonstrate "outstanding universal value." They include places like Ecuador's Galapagos Islands and California's redwood forests.
There are 229 sites throughout the world, and a report from the WWF found 114 of those are under threat from various types of industrial development.
Illegal logging is hurting Madagascar's rainforests, and Belize's Barrier Reef Reserve System is being damaged from multiple factors, such as coastal construction and pollution from agricultural runoff.
The WWF report says more than 11 million people worldwide depend on a World Heritage site for food, water, shelter or medicine.
The group is calling on governments to block projects that threaten these sites and urging businesses not to fund them. Instead, it wants the focus to be on projects that encourage sustainable development.
This video includes clips from UNESCO TV / TBS, National Geographic and World Wildlife Fund.