In our metaphorical journey, every step along that route from the middle of the GGB going east takes us further back in time, at 1 million years per kilometer. Let's see how far along our route compares with how long ago, beginning with the time scale of the Holocene Epoch.
The Holocene Epoch began 11,700 years ago when the last major northern-hemisphere ice age ended. As a calculation exercise, let's determine how far on our route you would need to travel to hurtle backwards to the faraway time of 11,700 years ago, as the ice sheets retreated and the Great Lakes formed.
Calculate how many meters of distance are equivalent to 11,700 years, using the metaphor-conversion-factor of 1,000,000 years per kilometer. In other words, if 1,000 meters = 1,000,000 years, how many meters is 11,700 years?