What we see in the picture is the predecessor of the current Clock Tower. This was the first lighthouse in the harbour and was built in 1772, although its origins date back to the seventeenth century when it was just a wooden structure while the dock was being built. The astronomer P A Méchain used the lighthouse as a surveying point between 1792-1798 to invent the metric system.
In the lower part of the bulwark was the Port Authority with the naval command, the passport office, sanitary control and the practice house, until 1903 when it was demolished. The lighthouse was preserved but the four faces of the clock were added.