A giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment is pictured at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer

A rocket is pictured on a giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment is pictured at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer

A tear gas mask is pictured on a giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer

A giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment is pictured at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer

A giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment is pictured at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer

A giant, so called "Tank Bike", driven by an engine of a T55 tank and constructed of former military equipment is pictured at a bike fair in Hamburg, Germany, February 25, 2017. REUTERS/Fabian Bimmer