Left to right are: Thomas Hamilton Obelisk in the Old Calton Hill Cemetery, the Governor's House & Waverley Station, the Dugald Stewart Monument, St. Andrew's House, and Nelson's Monument. Nelson's Monument commemorates Admiral Lord Nelson, who died at Battle of Trafalgar in 1805.

In 1852, a "time ball" was installed in Nelson's Monument so that ships in the Firth of Forth could synchronize their clocks. Later, in 1861, the "One O'Clock Gun" was established at Edinburgh Castle to provide an audible signal when fog obscured the time ball. The time ball was operated for over 150 years, until it was damaged by a storm in 2007. In 2009, as part of the restoration of the monument, the time ball was removed and the mechanism repaired. The time ball was brought back into service on September 24, 2009, and is now operated manually, based on the firing of the "One O'Clock Gun."