Right now, it has 28 member states: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Ireland, Latvia, Lithuania, Luxembourg, Malta, The Netherlands, Poland, Portugal, Romania, Spain, Slovakia, Slovenia, Sweden, and The United Kingdom.
The inner core is solid because it is made of very dense, or heavy, materials - like iron and nickel. Even though it is very hot, these materials don't "melt" very easily, so they stay solid. Also, pressure due to the weight of the mantle and crust, atoms are forced together as solid.
In the mantle which is below the crust
