Vacancy is an acute problem in the urban environment. Regardless of whether it is only floor-by-floor or in the entire building - vacancy remains.

The vacancy ratio in office space accounts to the percentage of office space available for rent that stays unoccupied. Office space that is, due to other reasons (e.g. lawsuits, construction activities or decay or private use), not available at the rent market is not covered by these numbers.

For Frankfurt in 2020 (during CoVid 19-pandemic) a vacancy ratio of 6.9 % was measured. Compared to other German major cities the ratio in Frankfurt is the highest (Hamburg: 2.6 %, Berlin 1.2%, Cologne 2.4%, Munich 2.2%, Dusseldorf 5.3%) ⁽¹⁾. Back in the year 2000 shortly before the burst of the new economy bubble the ratio used to be only 2 %. Shortly after the burst, it reached a height of 18 %. Since 2017 office related vacancy is on the rise again. A study commissioned by a local city office predicts the ratio to further rise. For the year 2029 the study estimated a vacancy ratio of 10 % ⁽²⁾.

Reasons differ from general oversupply to very particular local circumstances and the preferences of new buildings over old stock. A structural change in the banking sector which tends to fewer employees needed, home office and real estate speculation are further amplifying factors. Especially in Frankfurt - famous for being the finance capital of Germany - many high rises are owned and used by the same companies. Those inflexible ownership structure, which makes it difficult to adjust to a change in the demand. Asynchronism between the planning of private and public investors, the capacities of the construction industry and the actual demand are reflected in the urban real estate market, as well. At the same time, the fast inflation of real estate prices in Frankfurt during the last ten years recently have been evaluated in the UBS' Global Real Estate Bubble index. The UBS Wealth Management 2021 study ranked the risk for a real estate bubble in Frankfurt higher than for Toronto, Hong Kong or London ⁽³⁾.

Within this article I explore the abandoned skyscrapers that appeared and disappeared in Frankfurt's skyline and outskirts during the past five years. While useless for the real estate standards, these skyscrapers temporarily served as movie locations (theater as well as shooting location); retreats for homeless; adventure spots for juveniles, training grounds for police and fire brigades. Parallelly, some "urban mining" was going on as cable thieves scavenged the buildings. Garages and parking lots were used by neighbors. In another case, a second-hand vehicle dealer used the free space to store tires and other spares.

Der Kraken / Lurgi Haus - Build in 1987 Der Kraken (engl. the kraken) used to be one of Europe's biggest office buildings. Der Kraken has 87.000 square meters (vacant) office space.

Kraftwerkunion (KWU) - Former headquarters of Siemens' nuclear energy branch

District army recruiting office - 24 floors in the suburb abandoned since military service reform from 2011