The Netherlands Antilles, the autonomous territory of Netherlands since 1954, include 5 islands:
1, Sint Eustatius
2, Sint Maarten
3, Saba
4, Bonaire
5, Curacao

These 5 islands comprise of Netherlands Antilles before 10/10/2010.

From 10/10/2010, 2 of the 5 islands, Curacao and Sint Maarten, became the autonomous countries within Netherlands, similar as the autonomous countries within Russia,
The remaining 3 islands, Sint Eustatius, Bonaire and Saba, combined together and became a special administration area within Netherlands, similar as Hong Kong and Macau to China.
Since then Netherlands Antilles disintegrated.

In addition, Netherlands Sint Maarten and French Saint Martin share a same island, the south part of this island is Netherlands Sint Maarten, and the north part of this island is French Saint Martin.