What is the best thing to do in Curacao?

I planning on a Southern Caribbean cruise in early July with stops in Aruba, Curacao, and Grand Turk. I've been on several cruises before but never been to any of these places. What are the must do things at each place?

I'm interested in excursions too but also just best beaches or places to see on your own.

FYI...Part of the group is older and can walk but can't do any long distances or hiking or anything.

AND - I'm looking for something possibly adventurous to do with my 17 yr old nephew

Thanks!!

We just got back from Carnival Conquest cruise with a group of 16...age 6 to 61. Did the Irie Bus tour and WE LOVED IT! 25 per person including 3 hr tour and ice cold beer, water,soda. They responded quickly to my email when I booked our group. Friendly and informative tour!

Oops..tour was in Curaçao! They met us at the end of the pier.

In Aruba, we have enjoyed a 3 hour morning tour of the island and then time at Palm Beach by taxi.

In Curacao, there is so much to do in Willemstad. Some take the Trolley Train and then walk around to the many historic sites.

In Grand Turk, the cruise port area has plenty of activity.