Vienna Opening-Eifel Gambit

1. e4 e5

2. Nc3 Nf6

3. Bc4 Bc5

4. Nge2 b5

The Eifel Gambit involves black sacrificing the pawn on the b5 square, which is similar sacrifice in evans gambit where white sacrifices the pawn on the b4 square. In this position black wants a better center control and active pieces and space on the queen side.