We’ve entered a new year and a new decade, having closed out the first 20 years of the millennium with no shortage of architectural projects that have markedly changed the built environment. Whether through interdisciplinary approaches to design, innovations in materials and technology, or new programs around placemaking and sustainability, buildings and spaces have defined the times. To that end, we’ve asked a group of leading architects and designers to get the conversation started by sharing their top picks for the seminal buildings and spaces of the last 20 years.