Website of the US-based Council of Foreign Relations containing numerous articles and commentary on contemporary security concerns around the world.
Europe-wide major thinktank with numerous in-depth reports.
The UN Instraw (UN International Research and Training Institute for the Advancement of Women) website provides a guide to numerous sections on gender issues including security.
A useful general website containing articles and information about terrorism.
These are the general websites for the UN, Council of Europe, and NATO and will lead you through an enormous number of subsites with important documents and other interesting material.
Website of the Permanent Mission of the Russian Federation to the European Union provides an alternative perspective which outlines, among other things, the emergence of a polycentric global order as a counter to claims of US hegemony.