What are the must-see attractions in Lisbon for seniors?

Seniors may particularly enjoy visiting:

Jerónimos Monastery: A UNESCO World Heritage site showcasing stunning Manueline architecture.

Belém Tower: A historic fortress offering insights into Portugal's maritime past.

Alfama District: The oldest neighborhood in Lisbon, known for its narrow streets and traditional Fado music venues.

Lisbon Oceanarium: One of the largest aquariums in Europe, home to diverse marine life.