The Madiera portal
…harvests statistical datasets and variables published on the Semantic Web from all the largest European social sciences data archives, organizes them using a set of multilingual thesauri and taxonomies and makes them available through a responsive and highly customizable Web interface… The Madiera project has provided a common integrated interface to the resources of the majority of the existing 20+ social science data archives in Europe.
This portal allows you to search in one place for European data across multiple sources. In many cases, access is available to the general public. In these cases, some online analysis of data is possible along with documentation and download.