An extension of the Passeig Lluís Companys in the park is the so-called Passeig dels Til·lers.

On the right-hand side of this road there are four constructions from the World Fair. The first one is the Castell dels tres Dragons, erected between 1887 and 1888, and designed by Domènech i Montaner. Despite the speed of construction it did not fulfil its mission, which was that of being the Café- Restaurant of the Fair.

The Castell dels tres Dragons now houses the Zoology Museum, which includes a vast display of stuffed animals, a large sound archive, library and bookshop, and organizes various activities such as exhibitions, conferences, etc.