Last Saturday, the Energy Department held its first Energy All-Stars event -- an afternoon of TED-style talks from America's energy leaders. Over the course of the afternoon, attendees heard from experts from both the public and private sectors. The lectures covered the gamut of energy topics, from finance to climate change and technological innovation.

From Mars to Venus, Bill Nye the Science Guy looked to space for lessons about Earth's atmosphere and the growing threat of climate change.

Former Michigan Governor Jennifer Granholm proposed an energy race-to-the-top for state governments to compete against one another for clean energy funding, while Los Angeles Mayor Antonio Villaraigosa touted his city's accomplishments in the energy sector.

Michael Liebreich, CEO of Bloomberg New Energy Finance, highlighted the impressive growth of investments in renewable energy around the world, while also cautioning of the challenges that lie ahead.

Attendees also heard from other speakers from the private sector, including Dr. Susan Tierney, managing principal of the Analysis Group and former Assistant Secretary of Energy, and Doyle Beneby, President and Chief Executive Officer of CPS Energy. Secretary of Energy Steven Chu offered opening and closing remarks highlighting the rapid pace of technological advancement in the 20th century -- from horses to street cars to automobiles.

Check out the videos above for some of the highlights from the day.