I recently read "1177 B.C.: The Year Civilization Collapsed" by Eric H. Cline and although it focuses on the Late Bronze Age Collapse, it emphasizes how thoroughly connected the civilizations of the eastern Mediterranean were prior to the collapse. Trade was obviously common among close neighbors (such as Egypt- Crete or Crete- Greece, etc.) but the trade network was far more complex than that. Covered in detail in the book is the Uluburun shipwreck, which is believed to have been a merchant vessel that contained copper from Cyprus, ebony from Nubia (Sudan), glass from Mesopotamia, jars and pottery from Canaan, Egyptian scarabs, swords and knives from Italy and Greece, a stone mace from the Balkans, and tin and lapis lazuli from Afghanistan.

Mesoamerican civilizations show signs of long distance trade and contact with other groups as far away as Cuba. I can't provide a source but I also remember a podcast mentioning the Aztecs receiving pottery and other goods from what is now Arizona and New Mexico.

Otzi The Iceman's gear supports at least some (relatively) long distance trading occurred during his time.

Of course, none of this confirms direct contact between these civilizations, as a traded good could easily be passed from merchant to merchant and eventually wind up far from where it originated. However, it does suggest the possibility of these civilizations being in direct contact.

The Greek explorer Pytheas is recorded as having reached and explored the British Isles and Scandinavia, being the first recorded contact with the Celts and Germanic tribes. He also may have seen Stonehenge and reached the Arctic Circle.