The three architecture teams in contention to renovate the Martin Luther King Jr. Memorial Library presented their ideas to the public on Saturday.

It’s a long presentation, but worth it to see what the teams — Mecanoo/Martinez + Johnson Architecture; Patkau Architects/Ayers Saint Gross with Krueck +Sexton; and STUDIOS Architecture/The Freelon Group — have dreamed up. (An urban farm on the roof is discussed at the 2:39 mark.) Feedback about the designs can be submitted here.