What is "antilia"

Antilia is a private home in South Mumbai about which Ratan Tata famously said, "It makes me wonder why someone would do that. That's what revolutions are made of,". It is owned by Mukesh Ambani, Chairman of Reliance Industries, and includes a staff of 600 to maintain the residence 24/7. , it is deemed to be the world's most expensive residential property, after Buckingham Palace, which is designated as a crown property. It is thus the world's most expensive private residential property, valued at $1 billion. It is clearly distinguished in the Mumbai skyline due to its unique design.