Nepal has remained a land of diverse peoples and cultures comprising more than one hundred ethnic and caste groups and 92 different languages. Each ethnic and caste group has its own common culture. Kathmandu, the capital city of Nepal, is one of these multi-ethnic (both in language and culture) ancient places. Dozens of monuments that date back thousands of years are located in the Kathmandu Valley. All of the heritage sites have to a certain degree been affected by devastating earthquakes in April and May 2015. This study shows that the most popular tourist and pilgrimage destinations like Kathmandu Darbar Square, Bhaktapur Darbarsquare, Patan Darbar Square, Swayambhunath Temple Complex, Dharahara Tower, Pasupatinath Hindu Religious Complex have been massively destroyed. It analyzes the socio-economic consequences to the inhabitants of World Heritage Sites after the devastating earthquakes in the Kathmandu Valley. Initial findings indicate that beyond the impact on the employment of tourist guides, domestic and international current tourists flows have decreased by 41% and that 23% of local craft shops, curio shops, hotels, restaurants, grocery stores, footpath shops have closed down as a result of the 12% decrease in the travel and tour industry. The effects to the supply chain are significantly shown in particular collapsed sites. The impacts on the National economy are similarly negative. Consequently, this study has recommended to the government of Nepal and other donors to reconstruct the collapsed World Heritage Sites and to preserve the other existing World Heritage Sites with earthquake-resistant structures as soon as possible.