Karachi a city brimming with happenings. Port city with lots of history pre partition of India-Pakistan. Night life is fun along the long cornich at the beach. Shopping is great at the new plaza malls or for ethnic bargains, check out the Zainab bazaar. Food is great specially at Clifton and do try out the late night paan(betel leaf) shops or qulfi(icecream) in bahadrabad. Lots of fun sports club in Defence area(membership required). Sight seeing places are Tha Qaid's mosoleum and paradise point worth visiting. Overall a must see city when visiting Pakistan.
Do be careful of roadside unexpected robberies that happen to few but do be watchful!