What are some cool attractions in Panama?

Sights to see, basicly anything interesting that I can see when I go on vacation.
thanks!

I lived there for 2 years as a U.S. military serviceman . And I've read the other answers which I will concur that the suggestions were good ones .

But the single most interesting and lifelong valuable thing to do is -- THE JUNGLE . Go on guided tours in different areas . Walk slowly and just use your eyes to discover thousands of things you won't see back home here in the U.S.
The many varieties of monkeys (nothing like observing them in a zoo) , the trees (unique twisted wood and amazing growth), the flowers (oh man, so beautiful and even some that grow on tree branches and not in the soil!) , over 300 varities of birds (Panama has more varieties than anywhere in the world) , the butterflies (some of the rarest and most gorgeous species ) , the animals (amongst many you've never seen, even in a zoo, you'll likely see some coatimundi families that are a joy to watch) .

Like I said , I served in the U.S. Army when I was there and now 25 years later, the above mentioned attractions are still what bring back the fondest and most valuable memories .

Email me anytime if you'd like to ask anything about Panama .

Boca Del Toro. Beautiful. The Canal. Neat, but boring after a while.

Panama has a lot to offer, the canal is one of the main attraction but Panama has a lot of beautiful places and things to do you will never imagine.
I recommend San Blas, Bocas del Toro, Chiriqui has beautiful mountains, Pearl Islands, try to visit the Pacific and the Caribbean you will see the different between oceans, if you have the opportunity to go to Coiba you will be surprised. In the city visit casco viejo, panama la vieja and try to make a tour in La Chiva Parrandera is a party bus style and is a lot of fun. If you have any question please let me know, I can provide you information and even guides in Panama. joel.lopezh@yahoo.com
You will have an amazing experience in Panama.

well the best form to have an enjoying trip is by scheduling your time while you are in Panama.
the best places to visit in Panama City
Panama Canal, the ruins of Panama la vieja,Causeway, Casco antiguo

if you go to Colon(it's another province located out of the city 80 KM)
Portobelo: was the first place where the Spanish arrived to Panama in the 1800'( the ruins of Portobelo is a Proof of the Spanish colonies that existed there)
Isla Grande ( there is a boat that take the visitor to the Island it's after Portobelo.

Bocas del Toro
definitely you have to go to this place this is the place where you'll find the best beaches of Panama, you can do several kind of activities;snorkeling,swiming,scuba diving,etc.

San blas
it's one of the best place to sightseeing surrounded by the beauty of the forest and the variety of animals, learning a bit of the "Kunas", San Blas has Crystalline water. it's a quite place so you'll feel confortable

Boquete-Volcan
those places have a good weather you can do hiking.

those were the places you can visit in a short period of at least of one week, there are more places but you'll have to find out by yourself in a tourism guide.