Neptune.

The Neptune Fountain is a Neoclasic monument, it was made between 1780-1784.

This monument is in “Plaza Canovas del Castillo".

The creator of this fountain was the arquitect Ventura Rodriguez under the comands of Carlos III.

The material of this fountain is white marble from Toledo. It is some of the iconographic programe inspirated in the Gerco-Roman Mythology (Neptune was the Roman god of the seas)
Other details of Neptune fountain: 

Nowadays the Athletico de Madrid football club celebrate here when it wins.

Other important buildings and sites in this area are:  

 - Museums like "El Prado", "Thyssen Bornemisza", "Cosmo Caixa", "Reina Sofía", Sorolla and others
- Ritz and Palace hotels are not far from here
- Bars: "El museo del jamon" Is a tipical bar of Madrid to eat Spanish Ham, it isn't a real museum. 

It is important to mention and worth visiting "The old Jeronimos church" and "La plaza de la lealtad" (Loyalty Square) and the financial area: here is the Madrid stock exchange.
For further information: http://www.77madrid.com/fuente_de_neptuno.html