Without wanting to sound rude, there are a variety of really good guide books and travel sites, including this one, that list all the major and minor attractions in every country. It would be a better idea for you to visit those first and then come back with specific questions that experienced travellers can help you with.
I could list off a whole range of tourist sites, the Taj Mahal, the temples of Kajuraho, the Ajanta caves, Jaisalmer …But it would all be absolutely worthless unless I know a little more about you, your interests, what would you like to see? What would you like to do? Are you alone or with children by the tag on your question?
Help us to help you?