Sally from Cali

No, it is not possible to see all of those sites in 2 hours, especially if you want to enter into each of them. What further complicates your timeline is the time it takes to enter and move through each site (particularly the monastery and the tower). This is regardless of if you have pre-purchased tickets and despite what companies say, there are no skip the line tickets for the monastery. The monastery alone could take up the full 2 hours between getting in, looking around and taking pictures. Moreover, while these sites are close to each other, you will still need to factor in some amount of (I presume) walking time. At most, I would suggest (and still not sure it’s possible within 2 hrs), going inside the monastery and then taking pictures of the Monument to the Discoveries and the Belem Tower from the outside only (no tickets, no queues). If you had 4 hours, I would say you could go into 2 of them. I’ve never been inside of the Monument of the Discoveries, but by most accounts it’s not really worth it to go inside. I can vouch for the Monastery and the Tower and they’re both worth taking your time to visit. Therefore in 4 hours you could visit the Monastery, pass by the Monument, and then end with a visit of the Tower. Hope this helps you plan.