More than 16 years have passed since the first meeting of Europe's environment ministers at Dobris Castle in June 1991. Since then Europe has changed enormously, as has its environment. In this, the fouth assessment report, we underline the changes that have occurred in the environment and socio-economic context to help explain many of the environmental trends that have been observed. We identify successes and improvements but also register old legacies that need further effort such as, in particular, air pollution, water issues and contaminated sites. New threats, which challenge piecemeal solutions and call for integrated strategic measures at European and global levels, are described such as persistent chemicals in the environment, biodiversity loss, sustainable production and consumption and climate change. And a new overview is given of the state of European marine areas and inland seas.The current assessment makes a number of things clear - first, the type of challenges that we face, and second, the barriers to progress.