What chain is IOTA on?

Could you please enlighten me on the matter of IOTA's blockchain? I'm curious to know on which chain exactly does IOTA operate? Could you clarify if it's a standalone blockchain or perhaps a part of a larger network? I'm quite intrigued by this cryptocurrency and its unique technology, so your insights would be greatly appreciated. Could you also elaborate on any unique features or advantages that IOTA's chain might possess? Thank you for your time and expertise in this matter.