Hi Sushmitha,
Himachal Pradesh is a gorgeous state and has so many beautiful places to visit. Since you will be there only for 3days, I suggest you go through this compilation of the best places to see and best things to do in Himachal Pradesh and choose what suits your travel style. https://www.tripoto.com/himachal-pradesh
My personal suggestion would be to embark on one of the treks. Hope this helps!
Regards, Senneil
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