I've somehow never put this together or paid that much attention.
I just always assumed it was some generic place or the Moon Kingdom, but you're right, it looks very east or south-east Asian. The openings always have such epic stuff happening that we never see...but that's anime, for ya.
I pointed it out before but the Tenkei Kingdom (via it's Kovil/Pagoda-eaque towers) is likely inspired by the
Prambanan Temple, a Hindu temple in Indonesia dedicated to the Trimurti - Brahma, Vishnu and Shiva whom the Starlights take inspiration from.
Notice the 3 main towers each representing one of the Starlights.
You have to remember the the Openings (and Endings as well) were always super spolilery:
- Classic already showed Venus a whole arc before she debuted as well as the Princess Serenity reveal.
- R explictly showed Usagi becoming Neo Queen Serenity before it was even confirmed.
- S showed the butterflies (Super Sailor Moon's symbol) from the very first version.
- S also depicted the girls praying in the garden of the Silver Millennium in the Opening and the group shot also showed them there, the Ending also showed all the girls during the time of the Silver Millennium - there were a couple of call backs to the Silver Millennium in the beginning of S, possibly diving into the lore and linking the Outers to their past lives but eventually dropped.
- SuperS predominantly showed Elysion in the Opening and Ending but we never see it in the show, it's only mentioned.
- Stars' Ending already showed angel-winged Usagi.
- Stars opening showed several events of the season, Mamoru taken away by an evil entity, Chaos corrupting Galaxia's Star Seed, Usagi spreading her light and releasing Star Seeds all over Tokyo, the Tenkei Kingdom being revived and Galaxia, as the Light of Hope, diving into the depths of the galaxy.
I suppose the writers intended to go the Classic season route and eventually introduce the 'Find the Princess' arc but it was eventually scrapped.
I really wished the girls had gone to the Tenkei Kingdom, who knows perhaps it is where the final battle was thought to take place in the very early beginnings.
Starlight Honeymoon Therapy Kiss
I love these coloring lights they used to do before!
Why don't they do it anymore?!?!?
Toy commercial!