In 2007 a Fish Ladder (“Fischaufstieg”) was opened with an adjoining observation room that offers a view into the underwater world of the river Lahn at the weir near the Klinkelsche Mill in central Giessen — Das Lahnfenster Hessen (The Lahn Window Hesse). In 2014 it was extended and made even more appealing to visitors. The observation room has approximately 400 , and offers a glimpse into the Lahn’s underwater world through windows facing into the Lahn and Fish Ladder. Equipped with large windows to the fishway, but also with a direct view into the Lahn you can observe here the fish in their natural environment. Another window gives the visitors an insight into a shallow water zone, the "nursery of the fish". The shallow water zone is designed in a way such that there are mainly juveniles because they feel safe from enemies. In the summer one can observe  whole swarms that draw their circles.  The pleasantly designed room invites the visitor to sit back and relax. With patience and a little luck one can see a variety of fish at the Lahnfenster, including: Brook Trout (Bachforelle), common Barbel (Barbe), Perch (Barsch), and Pike (Hecht). A variety of crabs also lend themselves to frequent sightings as they move about on the riverbed and settle near the viewing windows.  An adjacent pavilion was built at the observation station as part of the expansion and can be used for training courses and lectures as well as exhibitions. This river visitor information center is also suitable as an out-of-school venue for school classes and kindergartens. Additionally, a boat exit directly at the opposite river bank allows boaters to visit the complex.  Furthermore, the platform of the Lahnfenster Hessen is worth a visit outside the regular business hours. The LIFE Environment Integrated Project 2014 Living Lahn was used to build a touch kiosk, where visitors can get daily information about the river Lahn and its inhabitants.