Wide open public spaces can be incredibly difficult to shoot, as you have no control over the lighting or the movement of people within the space.
A lot of extra frames have to be shot to control the dynamic range within the environment, further frames to capture people in the positions most favourable to the composition also have to be shot.
On top this every single image was a vertical planar stitch using the shift movements on specialist the shift lenses I have, the benefits of this approach allowed me to capture wider angles of view without compromising the vertical lines.
In short these shots would have been impossible without shift lenses, and the technical knowledge to put the resulting images together.
A lot of time went into the process on location and again later in post-production, in order to produce these high end images.