Denver. Viaducts. Denver has $1,500,000 invested in bridges and viaducts. Municipal Facts Nov. 27, 1909 P-1-5s, 15 Right of way. Republican . Jan. 26, 1888 p.5, c.3 16th Street viaduct to be remodeled. RMN Jan. 10, 1952 p.32 Council approves $250,000 for new viaduct from Valley Highway to Lipan Street. RMN Jul. 18, 1956 First one built in Denver was 23rd St. - given to city by Nathaniel P. Hill. De denver Municipal Facts 1909 0.