About the location
Don't forget your tripod because there is no natural light. If there are many people, you might even use an ND filter to get even longer exposures to smoothen out passing people.
The Elbtunnel is located in Hamburg, Germany. It can be passed by car and on foot. Obviously only the last option is relevant for photography. The tunnel is extremely long and therefore offers a nice mood for different types of photos.
Don't forget your tripod because there is no natural light. If there are many people, you might even use an ND filter to get even longer exposures to smoothen out passing people.