Cortan because ellos means they and they is plural. Corta would be for ella/el/usted
I'm not really sure what you are specifically asking for but the park is located in the city of Madrid Spain. It belonged to the Spanish Monarchy until the late 19th century,then it became a public park so I think your looking for a sentence to writ in Spanish, so you could say this " En El Parque del Buen Retiro uno puede caminar alrededor y visitar los paisajes bellos que el parque ofrece.
hope this helps!
