Answer:
Because the place served as a zero milepost of a railroad connecting Midwest to East coast.
Step-by-step explanation:
Back in the year 1837, when the state of Georgia has agreed to establish a railroad connecting the Midwest with the East Coast, it was believed that there is a need for establishing the endpoint often referred to as "Terminus".
To do this, a large stone was sunk in the present-day Atlanta in Georgia serving as the end of the railroad line.
Hence, Atlanta has a connection to the meaning end of the line "Because the place served as a zero milepost of a railroad connecting Midwest to East coast."