PixelMap is the oldest verified collection OpenSea, launched on November 17, 2016.  PixelMap is the first NFT to store image data directly on the Ethereum blockchain.

Each tile is truly owned by the entity that purchases it. Because the data itself, not just a pointer, is stored on the Blockchain, nothing short of every single Ethereum node shutting down can eliminate the data.

The contract is designed so in the event that a tile owner would like to update the image, change the URL, or sell the tile for any amount they'd like, they can, without any central authority facilitating or controlling any part of the process.

In the event that PixelMap.io itself were to ever go down, the data, owner, and URLs for every single pixel remains on the Blockchain, and can easily replicate and display the overall image, as well as the historical changes.

The original contract in 2016: 0x015A06a433353f8db634dF4eDdF0C109882A15AB, Wrapper: 0x050dc61dFB867E0fE3Cf2948362b6c0F3fAF790b.