Sightings: A garden in the middle of a building

Update: I just realised that the garden may be accessible from the inside of building. Seems like there is a door.

I was walking along Clarke Quay on Saturday, when I spotted this building which made me very puzzled. It was a blue tower with glass windows, nice design, but what is strange is the garden in the middle of nowhere. There is a cave-in region where pots of plants are placed. For what reason, I do not know. Maybe to let the birds have a place to rest? The first thought that came to my mind was 'Man, the cleaners must have a hard time cleaning the garden'. Really strange architecture. Anyone knows which building I am talking about?