Ok, so Detroit has a lot of FIRSTS, dating way back to its colonial days. Let's try and round them up here! Be sure to provide a DATE and DESCRIPTION!

Below are some ones I thought of off-hand...

1701. First settlement established on the Lower Peninsula of Michigan.
1805-1847. First capitol of the Michigan Territory/State.
1866. First soda pop in America [[Vernor's)
1879. First city in the U.S. to receive telephone numbers.
1909. First mile of paved concrete - Woodward between Six and Seven mile
1913. Henry Ford's Highland Park Plant is the first in the world to utilize the assembly line process.
1920 [[?). First electronic traffic signal, Campus Martius.
1930. First international automobile tunnel in the world constructed between Windsor & Detroit.
1941. First urban depressed freeway - Davison Fwy - is constructed, spurring the development of no less than three more major interstates in the city.

Keep em coming! There are more!