A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity.
A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions.
Here are the top 20 tallest dams in the world.
| Rank | Name | Country | Height |
| 1. | Jinping-I Dam | China | 305 m (1,001 ft) |
| 2. | Nurek Dam | Tajikistan | 300 m (980 ft) |
| 3. | Xiaowan Dam | China | 292 m (958 ft) |
| 4. | Xiluodu Dam | China | 285.5 m (937 ft) |
| 5. | Grande Dixence Dam | Switzerland | 285 m (935 ft) |
| 6. | Yusufeli Dam | Turkey | 275 m (902 ft) |
| 7. | Enguri Dam | Georgia | 271.5 m (891 ft) |
| 8. | Vajont Dam | Italy | 261.6 m (858 ft) |
| 9. | Nuozhadu Dam | China | 261.5 m (858 ft) |
| 10. | Manuel Moreno Torres (Chicoasén) Dam | Mexico | 261 m (856 ft) |
| 11. | Tehri Dam | India | 260.5 m (855 ft) |
| 12. | Mauvoisin Dam | Switzerland | 250 m (820 ft) |
| 13. | Laxiwa Dam | China | 250 m (820 ft) |
| 14. | Deriner Dam | Turkey | 249 m (817 ft) |
| 15. | Alberto Lleras (Guavio) Dam | Colombia | 243 m (797 ft) |
| 16. | Mica Dam | Canada | 243 m (797 ft) |
| 17. | Gilgel Gibe III Dam | Ethiopia | 243 m (797 ft) |
| 18. | Sayano Shushenskaya Dam | Russia | 242 m (794 ft) |
| 19. | Ertan Dam | China | 240 m (790 ft) |
| 20. | Changheba Dam | China | 240 m (790 ft) |
