How do I "sightsee" in a class Bravo airspace?
Just call up ATC on the approach frequency and request flight following to see the location you're interested in.  They'll assign you a transponder code and any restrictions.  For example:


  N12345: "Houston approach, VFR request for Cessna 12345"
  
  Houston TRACON: "Cessna 345, say request"
  
  N12345: "Cessna 12345 is at 1200 ft, 3 miles south of Houston Executive, requesting flight following to overfly the Greenway Plaza area for sightseeing, aircraft type is a Charlie 172 slant Golf."
  
  Houston TRACON: "Cessna 345, squawk 4123."
  
  N12345: "squawk 4123 for Cessna 345"
  
  Houston TRACON: "Cessna 345, radar contact. Cleared into Bravo, maintain at or below 3,500, remain north of the University, advise when your sightseeing is complete."
  
  N12345: "Cessna 345 is cleared into Bravo. Will remain at or below 3,500 and north of the University. Will advise when complete."


Notice that it is preferred that you don't give your entire VFR request in the initial callup to avoid overwhelming the controllers if they're busy or not yet prepared to copy your entire request.

Just ask for "VFR request" with your callsign and wait for them to ask for the details.