Which Viking explorer reached North America around 1000 AD?

Leif Erikson, and unlike most claims of this kind it is archaeologically proven. L'Anse aux Meadows in Newfoundland is a Norse site with turf buildings, iron-working and characteristic artefacts, excavated in the 1960s - and in 2021 the wood was dated with unusual precision to exactly 1021, using a cosmic ray event of 993 that left a spike in tree rings worldwide.

The sagas describe several voyages and a place called Vinland, and the settlement did not last - probably a handful of years, undone by distance and by conflict with the people already there, whom the Norse called skraelingar. It was a supply base for exploring further south rather than a colony.

The interesting part is that it went nowhere. Europeans reached North America, wrote it down, and the knowledge simply did not propagate - no follow-up, no maps that anyone acted on, and Columbus set out five centuries later with no useful information about it. It is a reminder that discovery in the historical sense requires not just arriving but being connected to a society able to do something with the news.