Complex sentence: The San Sebastián del Pastelillo Fort: in today's neighborhood of Manga, called del Pastelillo (the cupcake) because of its low altitude to avoid being affected by the Castle of San Felipe whose cannons may have destroyed it if made taller.
Split into simpler sentences: The San Sebastián del Pastelillo Fort: in today's neighborhood of Manga. It is called del Pastelillo (the cupcake) because of its low altitude to avoid being affected by the cannons of the Castle of San Felipe which may have destroyed it if made taller.