NOTE: Franchise Spoilers
Two lighthouses stand tall. In both Bioshock and Bioshock Infinite, walking through their front doors is the first step in your adventure in two cities that share more in common than their architecture would lead you to believe. In Bioshock proper, the door leads to a bathysphere that takes you to the cold blackness of the underwater city of Rapture, deep below the sea. In Infinite, it contains the rocket that will launch you to the sun washed floating city of Columbia, high above the clouds. You only need to play the first five minutes of both these games to observe the duality at their heart- one is a descent into Hell, the other the ascension to Heaven.