SightseerG 5

To unlock this achievement you simply need to take all five of the helicopter tours of Liberty City. The company giving the tours can be found in the southeastern part of Algonquin. Not all of the helicopters will be on their pads at one time as they are continually flying tours, so you will have to keep track. Walk up to the helicopter you want to tour with and hold down the Y button to take the tour. Once the Helicopter is in the air you will have the option to basically skip the tour by hitting A, but it will count towards the achievement. Take all five of the helicopter rides and the achievement will be yours.