What this is

Squares is a collection of the Earth. The whole planet is divided into 25,165,824 squares of about 20 km² each, and every one of them is a token you can own.

It is an ERC-20 for the land itself and an ERC-721 for the parcels you hold it in, so you can trade a single square or sell a whole patch of ground in one piece.

Your square is a real place. It has a fixed position, an aerial photograph of the ground it covers, and a set of facts about that ground: how high it is, how rough, whether it is land or sea, what the nearest town is.

Some squares have something famous on them. The one containing the Colosseum is a Wonder; there are fifteen of those. Around 1,300 more hold a UNESCO World Heritage site. The rest are ordinary ground, which is most of the Earth.

The grid

The squares come from S2, a way of dividing a sphere used in mapping. It gives three things that matter here.

Every point on Earth is in exactly one square. No gaps, no overlaps, nothing left over. The map leaves a disc blank at each pole, which is the projection running out rather than the collection. Those squares exist like any other.

The squares are all roughly the same size. A grid of latitude and longitude is not, since a degree square in Norway is far smaller than one at the equator, so owning a square means about the same amount of ground wherever it lands.

And squares that are near each other have near-numbered tokens. That is what makes owning a lot of land cheap, below.

Why 25 million is possible

Collections this size do not normally exist, because a normal NFT contract keeps a record for every token and announces every token that changes hands. Buying one per cent of the Earth would mean a quarter of a million records and a quarter of a million announcements, far more than a block can hold. It is not expensive, it is impossible.

So this one works in runs. Ownership is not "you own square 4,001, and 4,002, and 4,003" but "you own 4,001 to 8,000", held as a single entry and a single NFT. Because neighbouring squares have neighbouring numbers, that is the shape real holdings take anyway.

Buying 251,658 squares costs about a quarter more than buying one, and a patch of land is one item you can sell in one go however much of it there is.

Announcing them works the same way. ERC-2309 lets one event cover a run of tokens, so the whole collection can be announced in a few thousand events rather than 25,165,824.

OpenSea reads it. Block explorers do not, so a purchase also announces part of itself one square at a time. A large holding appears on a marketplace over the following hours.

What is measured

Elevation: Average height of the ground inside the square.
Relief: The drop from its highest point to its lowest.
Terrain: Flat, Hilly, Mountainous or Alpine, from that relief.
Surface: Land or water.
Nearest place: The closest town, and how far away it is.

Heights come from open elevation data, coastlines and towns from Natural Earth, and the imagery from the Sentinel-2 satellites.

Tiers

Two tiers describe what stands on a square rather than what it is made of.

Wonder: 15 squares: the New7Wonders of the World and of Nature, plus the Great Pyramid. About one square in 1.7 million.
Landmark: Around 1,320 squares, from UNESCO's World Heritage list. About one in 19,000.

Both come from published lists rather than our own picks. The New7Wonders polls were public votes and are arguable, which is why Jeju is on the list and the Grand Canyon is not.

Every other tier is measured: Capital, Metropolis, High Altitude, Abyssal, Open Water, Land.

The contracts

Every address below is on Robinhood Chain and its source is published on the explorer, so the code that runs can be read against the code we describe. Nothing here has to be taken on trust.

Ledger ERC-20: 0x04cF5D0081cB7ab196b25b766BebCd6d2f8B12Fe Who owns which squares. One unit is one square, and holdings are stored as runs rather than one entry per square, which is what makes a whole continent transferable in a single go.
Collection ERC-721: 0xfcaaB62A1e40eDB1f11E7b4adC91dA184602be7A The address a marketplace lists. It holds no ownership of its own: every answer it gives is read back from the ledger above.
Metadata: 0x62b571a4097E008C4c9Ec17437c0FAbc3D7e1243 Turns a token id into its S2 cell, and points at where each square's picture and facts are served from.
Fee hook: 0x200d1d56A118E1B580684e69d61cF011D3C820cC Named inside the pool itself, so it cannot be swapped for another. It takes one percent of each trade in ETH as the trade settles, at a rate fixed in the code that nobody can raise.

Where to start

The map is the collection. Spin it, zoom in, and click any square to see what is there. Collection shows the squares in a wallet and lets you sort them by where they are or what they are made of.