A trophy in architecture is like a little decoration or ornament that is placed in a special spot on a building to show off something important or special about that building. Just like how you might get a trophy for doing something really great in a sports game, a building can get a trophy to show off something special about it.
Sometimes, the trophy might be a statue of a person or animal that is important to the story of the building. Other times, it might be a design or pattern that is unique and shows off the creativity of the people who made the building.
The trophy is kind of like a special badge that tells you something unique and interesting about the building. You might see trophies on buildings like churches, museums, government buildings, or even just fancy houses.