After visiting the grande theater in Manaus I also managed to visit the theater in Belem on my trip this time around. Both were built during the Amazon Rubber Boom of the late 19th. If I remember correctly the theater wasn't very popular before but now stands as a marvel and enriches Belem a lot.

For the one in Belem you must join a guided tour that takes you through the lobby and the main theater. It didn't go up due to renovation so I don't know if you normally visit there. I think you mainly go there for photos which most people were interested in taking anyway. The program starts every hour between 9am and 5pm (sans 1pm) and only mornings at the weekend. It's probably also closed for events so check first. On Wednesdays you even get free entrance which happened for me but it's only 10 real (5 with discount) so wouldn't be the end of the world. Note that there is a 40 people limit and they didn't seem to care about that on Wednesday as they don't even hand out tickets although they might care if it's A LOT more than 40. The lobby doesn't hold many people and the main area gets a bit tight at ~100.

So my tour was in two parts. First you assemble in the lobby, get a talk from the guide and can take photos for a good 5 minutes before there's MORE talk. The lobby is very nice to look at with details in each corner. I was very lucky that not only was I the only foreign guest but they also assigned a cool student with excellent English capabilities (and knowledge) to show me around on my own. In a way it was a private tour for me! After the original speech he explained all the details in the lobby and I could ask all questions I wanted before we headed out to the main theater. It was also before the others joined which made it an excellent visit. Being in the main theater room by yourself makes a big difference. Once the other group joined it was still nice but then it just seemed "normal".

With the guy giving me a private tour I could also ask many questions. The only thing I didn't understand is the "water" below the stage which is supposed to enrich the acoustics. Sounds wonderful but there are windows on the side and it would just flow out and into the basement behind...so I think he didn't get his message across and it just gives a nice acoustic sound due to the design or perhaps water was stored here another way.

Another interesting fact was that before the higher floors were for "poorer" folk. You'd get the best seats at the main floor and on the first floor. Upper floors lacked air flow (no aircon at the time).

In total the tour was maybe thirty minutes long. I didn't stay for longer because I moved faster and the rest of the group was still in the main area but I don't think they did much more than take pictures.

I think this and the theater in Manaus definitely need to be included as a UNESCO site. If you already saw one then I wouldn't think it's a must to seek the other although they aren't identical. Both cities, Manaus and Belem, have other things to see thus you should combine this easily.