What does a breathtaking discovery mean?

Solution 1:

You get some fame for being the first to discover a landmark. And while natural wonders will give bonuses to an outpost/city if you claim the region containing it (if you hover over the wonder, you'll see a pop up), landmarks do not.

Landmarks are terrain features that are named in Humankind, with no special effects on the tile yields. They are discovered through exploration and revealing the map, and have five different types: Lake, Mountain, River, Forest, Desert.

Once a landmark is fully revealed, the Empire that fully explored it will become the "discoverer" of the landmark and receive a bit Fame.