I think the Pioneer Place mall in Portland, OR would be another interesting example. It's made of four separate buildings in the middle of downtown (underground

I think the Pioneer Place mall in Portland, OR would be another interesting example. It's made of four separate buildings in the middle of downtown (underground parking only), connected by underground sections and skywalks, and directly adjacent to tram and bus transit stops. The buildings have an open atrium-style design, with skylight roofs that provide natural light all the way down to the connecting basement level.