Alien Invasions with Abductions

Alien beings had visited Earth at some point in our planet's history. Perhaps, they started their journeys here some two or so million years ago, which is a possibility. Someone said that it's more likely most of their travels here were in the last 5000 years, so they could ongoing watch & study our human evolution. Now us humans have seen signs of what seems like Alien activity, however we've not observed anything they've done for any long periods to understand their purpose. This scene could have occurred, but it would've been too crazy to strange for anyone to talk about. No one wanted to be persecuted as being disillusioned; to be pointed out as being into sorcery.