The birth of the global environmental movement, and with it environmental education, started with the publication of "Silent Spring" by Rachel Carson in 1962. Eighteen years later, the world was given a unique glimpse of the Earth from space through a photo that was almost never taken. A photo that scientist Carl Sagan insisted be taken, one that would endure to be a symbol of the Earth’s fragility and vulnerability. This photo, or the anticipation of seeing it first-hand, may have been on the mind of UK astronaut Tim Peake as he ascended into space in 2015. Fast forward to present day: the Earth is still under threat, from its water to its forests, and from its air to its biodiversity. It is us humans, living and depending on the Earth, who are the reasons why it is under threat. This year, Science Alive will highlight the importance of appreciating, understanding and acting to preserve the beauty and complexity of the Earth, this "pale blue dot".