Clark/Lake is the last Blue Line Station in the loop and where the Blue Line shifts from running beneath Dearborn Street downtown to head northwest and ends up under Milwaukee Road northwest of the loop itself. The station is underground with a single island platform that isn't part of the continuous long platform for the 3 Downtown Stations under Dearborn Street. On March 23, 1992 extensive renovations led to a free in-system transfer within fare control to the elevated lines in the Loop Directly above the station through two newly developed and retrofitted buildings. The station has a single crowded island platform that serves the two track like that have the normal arched ceiling held up by a line of cream colored beams. Modern florescent lights light the platform from along the arch. A unique feature are a couple of TV monitors that display flight information for travelers taking the Blue Line to O'Hare Airport. A visit at the station in 2017 (waiting to catch the Blue Line to catch a flight saw these monitors now turned off
Exits are at each end of the platform. At the more substantial southern end a staircase/escalator and an elevator lead up to an underground landing just above the platform this is signed as LaSalle/Lake. Sets of revolving doors are on each side of the landing. Going one way leads into the Thompson Center and transfers to the inner loop Purple, Pink, Orange and southbound Green Lines. A high exit turnstile leads directly out of here to an outside of fare control connection between the Thompson Center and 203 North LaSalle. Immediately are a part time bank of turnstiles (closed on weekends) that lead to an underground shopping area and food court of the Thompson Center. Escalators and a bank of two elevators connect up to the main street level fare control area and continue up to the elevated platform above the street. On the opposite side is another set of revolving doors to 203 North LaSalle that lead to elevators and escalators up to the Brown Line and Harlem-bound Green Line. At street level is a smaller fare control area on the north side of Lake Street. The other end of the platform has a secondary exit, here a single up escalator/staircase leads to a small part time fare control area. There are two high entrance/exit fare card only turnstiles and some (closed during off hours and weekends) regular of turnstiles. Streetstairs (that have been modernized in their own unique way with marble sides before glass windscreens and a wavy canopy) lead up to Wells/Lake. Specifically the NW and NE corners beneath Tower 18 at the NW corner of the loop (elevateds cover all four streets at this intersection making the subway entrances hard to see).
Photos: 1 taken on 3 August, 2011; 2-14 on 2 November, 2011; 15-40 on 4 July, 2013; 41-42: 31 August, 2017; 43-44: 15 February, 2019