Places To Visit in Delhi are so many. I really do not know, what to write or what not. Let me start from here, that there are no hills or sea at Delhi, but history is widely distributed here in the forms of monuments. few are mentioned below for your reference. 
As everyone knows Delhi is a capital of India.  Here you can visit many places like India gate, Qutab Minar, Rashtrapati Bhwan, Rail Museum, etc.
We can enjoy the evening lightings at India Gate.  Can enjoy metro travels.  We can taste some street foods also.

We can enjoy some talks also with local persons.  Here, we can roam around for the whole night, can spend our quality times in Markets every where.  We can visit temples like Jhandewalan, Hanuman Temple.  We can spend 3-4 days to visit main places in Delhi and can watch movies also in malls.  In winter we can enjoy Delhi like in Shimla.