Did the Millennium Start in Year 2000 or 2001?

Replying to @Gay Engineer 🇬🇧🏳️‍🌈 does the millennium start at 2001

Is anybody here born in 2000? : r/GenZ

2000 – 2001, New Millennium: On Teenage Sexuality (or lack thereof). And 9/11

New millennium｜Ricerca TikTok

The Millennium Drought in southeast Australia (2001–2009): Natural and human causes and implications for water resources, ecosystems, economy, and society - Dijk - 2013 - Water Resources Research - Wiley Online Library

Celebration for 2001 no cyberspace odyssey

2000 – 2001, New Millennium: On Teenage Sexuality (or lack thereof). And 9/11

Why was the new millennium celebrated NYD of 2000? Shouldn't it have been NYD of 2001, because that's when the millennium actually ended? - Quora

The Millennium Dome 20 years on… revisiting a very British fiasco, Architecture