NASA's Goddard Space Flight Center has release a YouTube video it says shows how Mars may have looked 4 billion years ago.

When the Red Planet was young, it appears to have had a thick atmosphere that was warm enough to support oceans of liquid water -- a critical ingredient for life -- and the YouTube video shows how the planet could have appeared at the time, the space agency said Wednesday.

Beginning with a flyover of a martian lake, rapidly moving clouds suggest the passage of time and the shift from a warm and wet to a cold and dry climate.

As millions of years fly by the lakes dry up, while the atmosphere gradually transitions from Earth-like blue skies to the dusty pink and tan hues seen on Mars today.

NASA's YouTube "tour" of Mars comes as it prepares to launch its MAVEN spacecraft that will study the planet's atmosphere.

The launch is set for Nov. 18 from Florida's Cape Canaveral Air Force Station.