Of course, there’s the Washington Monument. But the WM was constructed in the 19th century from human-scale blocks of granite and marble that machines of that time period could lift.
Here’s an obelisk only about one third as tall as the Washington Monument, but it is carved from a single piece of granite. It is a relic of unknown age, discovered in an Egyptian granite quarry.
We don’t know why it was never finished, but we must imagine they had plans and capabilities to remove the obelisk from the quarry in one piece and set it upright. It weighs about 1100 tons.
Could a single piece of stone with this dimension be quarried, transported, and erected today? It hasn’t been done, not by a long shot. It would take some fancy engineering. It is 10 times heavier than today’s largest construction cranes could lift.
Ben at UnchartedX makes the modest claim that this one relic is sufficient proof of an ancient technological civilization. There’s lots more evidence on his channel, beginning with the Pyramids.