That is because Indonesia is pretty much one of Southeast Asia's
most diverse countries. If not, then probably Southeast Asia's MOST
diverse country. There is no such thing as "ethnic Indonesian" or
"Indonesian culture". Indonesian culture differs from region to
region. In central Indonesia, you'll find a lot of Malay culture.
In eastern Indonesia, you'll find a mix of Hawaiian-like culture.
In Java, Sumatra and Bali the countryside is really beautiful and a
rich Hindu culture thrives here. You can also find a lot of ancient
Buddhist and Hindu temples in Indonesia like Borobadur.