First go to Pena Palace (no queues early), the second go to the Moorish Castle (the two main entrances are very close), there is a hall before entering the castle, a documentary inside, don't miss it! After entering the castle, first go to the lower tower on the right hand side, and then go anticlockwise along the city wall to the highest tower. View of the Pena Palace and overlook the entire city of Sintra! The gardens of the castle center are full of flowers.