To commemorate World Architecture Day today, we're taking a closer look at some of Boston's boldest buildings.

Boston University's Center for Computing & Data Sciences looks a bit like Jenga blocks, hence the nickname. It isn't just pushing boundaries with design — it's also poised to be Boston's largest carbon-neutral building.

Blink and you'll miss the small but mighty North End house. The 10-ft-wide and 30-ft-long building on Hull Street, aka the "Spite House," is home to a fascinating history.

Did you know this was our city's tallest building for 49 years? The John Hancock Tower might have nabbed the title, but this Greek Revival-style landmark is still a fixture of the Financial District.

Honorable mention goes to City Hall — the Brutalist-style building may not be easy on the eyes, but it's certainly a conversation starter.