Wander through Har Ki Pauri, a famous ghat where devotees take a dip in the holy Ganga. Observe Aarti ceremony during the evening.
Take a walk at Laxman Jhula, a suspension bridge. Visit Triveni Ghat, the confluence of three rivers. Meditate at the Beatles Ashram.
See the Robber's Cave, a natural cave formation. Visit the Mindrolling Monastery, a prominent Buddhist temple. Take a walk in the Malsi Deer Park.
Stroll through the colonial-style Lal Tibba, enjoy a breathtaking view of the Himalayas. Experience a cable car ride at Gun Hill. Go for a hike in Happy Valley.
Take a safari into the jungle, observe wild fauna and flora including elephants, tigers and panthers. Go birdwatching.
Indulge in a shopping spree, taste local cuisine and sip tea at Char Dukaan. Visit Kempty Falls, a natural waterfall and have a drink at The Writer's Bar.
For an extended trip, visit the Jim Corbett National Park, an additional four-hour drive from Rajaji National Park. Subtract a day from Dehradun or Haridwar if in a rush.