The black-and-white limestone pavings that grace the streets and squares of Lisbon are one of the many visual attractions of the city. Historically, they date back to Roman mosaics, but this form of paving came into widespread use only in the 16th century when trade began to flourish as a result of European voyages of discovery. To ease the loading and unloading of ships, the quays along the River Tagus were consolidated with river gravel. Even today, the many nautical motifs that decorate these pavings – dolphins, shells and ships – testify to this golden age. Michaela Hoppe