This is the 5514th most frequent Polish word.
tunelu
"Tunnel" (genitive or locative singular form in Polish).
Locative case, indicating location within the tunnel.
Zaraz po przejściu tunelu widzieliśmy piękny krajobraz.
Right after passing through the tunnel, we saw a beautiful landscape.
Genitive case, used to describe possession or relation to the tunnel, showing the tunnel is the object of construction.
Robotnicy pracują przy budowie nowego tunelu.
The workers are working on the construction of a new tunnel.
Locative case, describing the physical position within the tunnel.