besides malls & crowded chaotic beach spots Karachi is full of history. if you try to .. State of (India) Pakistan Building at I.I Chundrigar road [ The financial hub of Karachi ] , Merewether Tower, DJ science College & NED University OLD Campus, Khaliq Dina Hall, Hindu Gymkhana, The Majestic Sindh High Court building, Tomb of Mohammed Ali Jinnah saheb, Mohatta Palace, Jinnah Residency, Frere Hall is opposite Marriot u can cross road & walk through the place before 10 pm to go inside the art gallery.
best seafood is at Beach Luxury Hotel which is next to " Port Grand "
before u ask me for directions, please use google. - For the scuba diving club & deep sea adventure you need some referral or a member along. - for water sports best is water park at super highway but again you need to be with a family.