Serranilla Bank is a former atoll in the Caribbean Sea that is, as usual, disputed.
The three claimants to the reef are Colombia (which provides the colour scheme), Honduras (which provides the star arrangement in the centre), and the United States. It seems like I didn’t think they needed to be represented. The five stars also double as symbols for the five islets and cays the bank is made up of.
The crescent is a bit of a mystery to me. Apparently I thought that the bank would be crescent-shaped back when I made this design; it used to be an atoll after all. Turns out that the above-water portions mostly lie in a straight line as far as I can tell, though.