this is the link to the official page of the fort of copacabana, with more details on schedule, art expositions, and more.

on this link, a 360-degree picture of the view from the fort of copacabana can be seen. 

the cannons, copacabana beach, and the sugar loaf can all be seen by navigating this beautiful image by ayrton. 

the forte de copacabana is located at praça coronel eugênio franco, nº1, copacabana, posto 6, tel. 21. 2522-4460 or 21. 2521-1032.  the fort's official website is here.