Every great metropolis has its secrets: some tucked away in the annals of history and others hidden in plain sight. From the single golden fire hydrant in San Francisco to the strange shape of London's black cab to Berlin's pink pipes, city landmarks often embody unknown stories, some whimsical, some sinister, but all fascinating in their own way. Join us in Searching for Secrets as we journey back in time to uncover buried tales in cities across the globe, following local guides and historians on a six-part journey that is both travel expose and urban mystery.