Fuente de Neptuno o Fuente de la Princesa

This was the first urban monumental fountain in Zaragoza. Also known as Neptune, it was located in the centre of the city in the square formerly known as Plaza San Francisco, today de España. It served as a water supply until 1902, when it was dismantled and replaced by the Monument to the Martyrs.
The first stone was laid in 1833 to commemorate the swearing of the oath of the princess and future Queen Isabel II.
The sculptural work was done by Tomás Llovet, a teacher at the city's Fine Arts school. On top of the monument we can see Neptune, standing with a trident, as water flows into the fountain from the mouths of four dolphins. 

It took its inspiration from the Fountain of Neptune in the Paseo del Prado in Madrid.