What goes up, doesn't always come down. This cache brings you near the old Kinzie Street railroad bridge, which has been in this position since early 2001.
Here is some history of the structure taken from Wikipedia-
The first railroad bridge in Chicago, a floating pontoon bridge, was previously built on this site. Completed in 1852, it allowed trains to access the railroad's new Wells Street Station and subsequently industry on the north bank of the Chicago River. The original railroad bridge was replaced by a swing bridge in 1879 and replaced once more in 1898. In October, 1879, a disaster was narrowly avoided when a seven-coach passenger train with 800 people on board approached the open swing bridge too fast and was barely able to stop in time, ending up with its front wheels hanging off the approach road over the river.
As a result of increasing river traffic congestion, in 1907 construction started on a new bascule bridge, the same bridge still standing today, that would allow more space for boats to pass by on the river. The innovative design used a large concrete counterweight which allowed the bridge to be stored in the upright position and not interfere with traffic on the river. When a train approached, the bridge simply had to be lowered to allow it to cross. The bridge was designed to carry two railroad tracks across the river. Its superstructure consists of two spans constructed by the Strauss Bascule & Concrete Bridge Company: a 26-foot (7.9 m) plate-girder span on the west bank of the river and the 170-foot (52 m) movable main span that rests on the east trunnion pier. The size and weight of the main span, which, when completed would be world's longest and heaviest bascule span, required the trunnion pier to be constructed on foundations that extend to the bedrock 94 feet (29 m) below the river bed. To achieve this, caissons were sunk to a depth of 29 feet (8.8 m) below the river bed and then 10-foot (3.0 m) diameter wells were sunk the remaining 65 feet (20 m).
When a new train station (now the Ogilvie Transportation Center) opened in 1911, Kinzie Street railroad bridge was left to handle freight traffic only. In 1930 the Merchandise Mart was opened on the site of the old Wells Street Station. Merchandise Mart was built on air rights of the Chicago and North Western railway, and in the spring of 1932 the railroad opened a new freight house underneath the building that was designed to handle 1,000 short tons (910,000 kg) of outbound and 600 short tons (540,000 kg) of inbound freight per day.
During the second half of the 20th century the number of companies using the railroad for shipping on Chicago's near north side declined severely. The construction of the Columbus Drive Bridge in 1982 wiped out part of the right of way and the spur to Navy Pier was abandoned. Service to the Tribune Tower also ended in the 1980s, and by the 1990s traffic along the remaining section of the spur served only one customer, the Chicago Sun-Times, with only one train per day. The newspaper moved their printing plant out of downtown Chicago in early 2001 leaving no traffic across the bridge and it has since been permanently raised in the open position. On December 12, 2007 the bridge was one of 12 historic Chicago railroad bridges to be designated as Chicago Landmarks.