This year, TED turns 30. It’s a big, round anniversary — the kind that brings with it a welcome moment of reflection. In this session, we look backward and see how far the world has come in the past three decades. These speakers turn back the clocks and offer bold new ways to think about recent history.

Here are the speakers who appeared in this session. Click below to read a recap of each speaker’s talk:

Technology designer Bran Ferren wondered: Are we building things now that will stand the test of time? Read more.

Brian Greene was up next, for a short talk on the history of the universe. Read more.

Architext Marc Kushner gave a fascinating survey of the past 30 years of architecture. Read more.

Filmmaker Yoruba Richen, who made the documentary The New Black, looked at the fight for LGBTQ rights and how it’s related to the civil rights struggles of the past. Read more.

And this session concluded with a special surprise speaker: none other than Edward Snowden, beamed in from Russia on a telepresence robot, imploring us to defend the privacy essential to democracy. Read more.