Crosstemporal Gatherings

The Time Patrol Lodge in the Pleistocene Pyrenees employs Cro-Magnons. Two Patrol Specialists live among Beringians. In both of these cases, time travelers openly interact with prehistorical populations in ways that do not affect later history. Visiting a much earlier period of a single timeline might be like visiting an antipodean continent on a single planet. There is no direct contact between the populations but they might be linked by long distance travelers.

In SM Stirling's Island In The Sea Of Time (New York, 1998), at the Nantucketer's Fort Pentagon in England:

"There were as many Americans as locals in the bustle." (p. 547)

However, this is more like an interplanetary gathering. The Americans have not only crossed the Atlantic but also, before that, traveled from the future of a different timeline although most of the locals do not need to be told, and would in any case not understand, that.

The scene is described in colorful detail:

sounds - boots, wheels, hooves;
smells - stale water, woodsmoke, horse sweat, leather, cooking, dung;
locals - war chiefs, traders, porters, laborers, the curious, tattooed men from Ireland.