In 2010, a user sent 1 BTC to himself, and ultimately lost access to 8,999 BTC.

He restored an old wallet backup and discovered that the remaining coins had gone to an unfamiliar address. He didn't have the private key, and the old wallet file was lost forever.

Sixteen years later, according to Arkham, 8,999 BTC worth around $741 million are still sitting at that address.

The bitcoins are visible to everyone, but spending them without the private key is impossible$BTC $ARKM