After the boys escape from the police's raid of the tenement building, where do they go and why is the place they go so crowded on this particular day?

After the boys escape from the police's raid of the tenement building, they take a taxi to the Navaro Graveyard in the center of the city, since this is where they believe the stolen money is hidden based on the clues they have been following all of this time. When they arrive, they see that the graveyard is very crowded due to the holiday of The Day of the Dead.