Tarbela the 2nd largest dam in the world is in Pakistan.

As on 29-8-2008 Tarbela Dam Pakistan is 2nd largest dam in the world wit respect to volume of the material used for its construction.
For list of the largest dams click: World's largest dams

Few dams larges than Tarbela are under construction (UC), including the mighty 3 Gorges Dam (TGD) in China.