The verb form “hay” comes from the verb “haber” and is used like ‘there is / there are’ in English:
Hay un libro encima de la mesa. – There is a book on the table.
Hay unos libros encima de la mesa. – There are many books on the table.
Hay una libreria en la ciudad? – Is there a library in the city?
Hay juegos en el parque? – Are there games in the park?
¿Hay un hotel en el centro? – Is there a hotel downtown?
Sí. Sí hay. – Yes. Yes there is.
¿Hay algunos monumentos por aquí? – Are there any monuments around here?
No. No hay. – No. No there aren’t.