What can you do in el parque del buen retiro?

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!

This is not enough information. what exactly is your question