European Space Agency (ESA) is the international organization that deals with space exploration. The European Space Agency was founded in 1975. ESA has 20 permanent members :
Austria 
Belgium 
Denmark
Finland 
France 
Germany
Ireland 
Italy 
Netherlands
Norway 
Portugal 
Spain
Sweden 
Switzerland 
United Kingdom
Greece 
Luxembourg 
Czech Republic
Estonia 
Romania
Head office of European Space Agency is located in Paris
One of the ESA divisions- the European Space Research and Tecnology Centre (ESTEC) is situated in Nordwijk in western Netherlands. ESTEC is the European Space Agency’s main technology development and test centre for spacecraft and space technology. At ESTEC , there are about 2500 engineers, technicians and scientists, who work-on with mission design, spacecraft and space technology. Prior to the launch of almost all equipment that ESA launches is tested in some degree at ESTEC.
Another ESA division- European Space Operations Centre (ESOC) is located in Darmstadt, Germany. ESOC is responsible for controlling satellites and space probes. It is mission control for most of the space projects of the European Space Agency.
There is also European Astronaut Centre (EAC) that trains astronauts for future missions. It is situated in Cologne, Germany and Center for Earth Observation and Information Centre (ESRIN) which are located in Frascati near Rome (Italy).
Official EAC's site Official ESRIN's site
An another Esa's centre is The European Space Astronomy Centre (ESAC), which means Astronomy as well as Solar System exploration. It is located in Villanueva de la Cañada, close to Madrid in Spain and hosts the science operation centres for all ESA astronomy and planetary missions together with their scientific archives.
At Kourou in French Guiana is situated the Centre Spatial Guyanais (CSG). CSG is the European Space Agency’s spaceport. It is a good place for a spaceport due to very closed location to the equator , and that launches are in a comfortable direction over water. The European Space Agency has delegated to perform spacecraft launches from Kourou to the French space agency CNES and Arianespace company.
European Space Agency’s space flight program includes human spaceflight, mainly through the participation in the International Space Station Program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observations, science, telecommunication and designing launch vehicles.
The public private Italian company ALTEC offers engineering support and logistics in ESA's missions. Click here for more informations.