While the M&M wasn’t built until 1930, the land on which it now sits has a very colorful past. Before the Civil War, around 1830, the north side of Buffalo Bayou was a busy port, mostly used for cotton storage. . It was where the “cottonclad” ships Neptune and Bayou City left, filled with cotton bales and hiding soldiers, to attempt a surprise attack in Galveston Bay against the Union’s Harriet Lane. The Houstonians were victorious, and brought back 350 Union soldiers who were interred in the warehouse until the end of the war. After the surrender, Henry House and Co. (the owners, who bought it from the Allen family) refurbished the building and used it as a base for commercial operations stretching into Oklahoma and New Mexico. Although we do not know what ultimately happened to the warehouse, the sub-basement and tunnel that still lead to the bayou are believed to be the original structures from the 19th century.
Further reading: Louis F. Aulbach and Linda C. Gorski, “Buffalo Bayou ‘Cottonclads’ and Dick Dowling’s Irish guards: Houston’s Civil War Heros”, accessed March 2015 from http://users.hal-pc.org/~lfa/BB11.html