The front side of the banknotes depicts windows and gates. These symbolise the spirit of openness and co-operation in Europe. The 12 stars of the European Union (EU) symbolise the dynamics and harmony of today's Europe. The bridges depicted on the reverse side of the banknotes symbolise co-operation between the nations of Europe and the whole world.
The windows, gates and bridges on the banknotes are stylised illustrations – these are not actually existing objects and constructions.
Read more and see the banknotes at European Central Bank webpage..
The face side of all euro coins looks the same. The obverse sides of the coins have the national design of each country. Despite of that, the coins of all nations are valid in the euro zone.
The coins of all countries can be seen at European Central Bank webpage.
The story of the Estonian national euro coin can be read here.