First trip to Portugal in December
 

We are a family of five (husband and kids ages 22, 20 and 17) going to Portugal for the first time in December. We will be staying for a full 10 days, not included arrival and departure days. What are the destinations/sights/experiences that we should not miss? We are in the very preliminary planning stages; any suggestions are much appreciated!
Thanks,
Claudina

With just ten days I would concentrate in the area between Lisbon and Porto.

https://flic.kr/s/aHsjqbGicw