Colonnades...

A colonnade is the term for a long sequence of columns joined by their entablature, often free-standing, as in Bernini's famous curving colonnade at the piazza outside St. Peter's basillica in Rome (below).

A colonnade of single columns is termed a screen. When in front of a building, screening the door (Latin porta), it is called a portico. When enclosing an open court it is known as a peristyle.

Below: A single colonnade (screen) at Versailles

Built from 1685 on by Jules Hardouin-Mansart, the Colonnade at Versailles replaced a grove designed by Le Nôtre in 1679 (the Springs Grove). A peristyle accompanies the 32 marble columns. The triangular tympani between the arcades are decorated with low relief carvings depicting children. The arch stones are adorned with heads of nymphs and naiads. The famous group in the centre on a circular marble base was executed between 1678 and 1699 by Girardon: Proserpine Ravished by Pluto.

The colonnades at Stowe house:

Colonnades at Blenheim Palace

The colonnades at Russborough Hall

Above: a good example of a modern (and stunningly lit) colonnade
borrowed from The Laurel Hedge