When do you have long wait for the next flight, don’t stay in the airport but go and explore city.
On the way to Costa Rica we had 10 hrs wait on the airport so we decided to see famous Panama canal. We took one taxi for city tour (~80$) – little bit expensive but sometimes it is just easier. Here in Panama you can pay in dollars is 1:1 to panamas currency Balboa.
Canal is very famous and of course when you are in Panama City, you have to see it. Good place to see The Canal is Miraflores Locks with terraces and observation decks ($20 ticket). There is also museum and you can learn how they built it. It is long wait for ship to go through The Canal but still is faster then go around South America. We spent there around 2hrs. In museum you can get really interesting information e.g. toll for ships is between $300 000 to $400 000 but even up to $800 000 if greater cargo. It is not cheap.
We recommend to take a ride to Historic centre. It is small place but you can feel Panama’s climate. We visited Saint Joseph church with beautiful golden Altar and Cathedral Plaza.
Panama Viejo is part of the old Panama City and former capital of the country. Now they’re only ruins and near by you can visit museum.