I believe there are 27 sites involving the city's racial history that have been recognized as official Miigan Historic sites, many with those green historical markers. There are at least three additional commemoration that might be considered.
Rosa Park - She lived in Detroit for 39 years and continued her active role here.
Zachariah Chandler - He was, arguably, the city's most prominent abolitionist and, while in the Senate and as Secretary of the Interior, strongly defended the rights of the Freedmen and Native Americans.
Ralph Bunche - This Detroit native was the first African-American to win the Noble peace prize.
If any one wishes a list of the 27 sites, send an e-mail to 1701Motown@gmail.com