The present layout of Birgu's fortifications is mainly a result of the 18th century rebuilding by the French architect Charles François de Mondion, although the general layout dates back to the mid-16th century.
The fortifications consist of (listed going clockwise from Fort St. Angelo to Dockyard Creek):
Fort Saint Angelo – a large bastioned fort, originally a castle built in or before the 13th century, modernized between the 16th and 17th centuries by the Order of Saint John.
The present layout dates back to a major reconstruction by Flemish architect Carlos de Grunenbergh in the 1690s.
For more details about the fort's layout, see here.

An irregular enceinte, beginning from the moat of Fort St. Angelo and ending at the Post of Castile.
Its northern end was occupied by a battery, now partially dismantled.

Post of Castile (Maltese: Il-Prexxa, Italian: La Breccia) – the east extremity of the Birgu Land Front.
It was originally built before 1565 and played a crucial role in the Great Siege.
The present layout dates back to the 18th century, and consists of a retrenchment and a hornwork.

St. James Bastion – a two-tiered pentagonal bastion built prior to 1565 and redesigned by de Mondion in the 18th century.
Part of the original 16th century bastion was rediscovered during restoration works.

St. James Cavalier – a small pentagonal cavalier built on St. James Bastion sometime in the 18th century.

French Curtain – a curtain wall linking St. James and St. John Bastions.

St. John Bastion – a large asymmetrical bastion containing two of the three main gates of Birgu, designed by de Mondion in the 18th century.
A modern road passes through an arch in the bastion.

St. John Cavalier – a two-tiered cavalier built on St. John Bastion.
It was originally built prior to 1565, but was modified in the 18th century.
Minor alterations were also made by the British in the 19th century.

Couvre Porte Counterguard – a pentagonal counterguard built to protect St. John Bastion.
It was built during the reign of Antoine de Paule, and was modified in the 18th and 19th centuries.
The British developed its casemates into a barracks, which now houses the Malta at War Museum.

A curtain wall linking St. John Bastion to Dockyard Creek.
Originally there was a small bastion but this was destroyed in the explosion of 1806.

The entire land front is surrounded by a rock-hewn ditch, which also includes a caponier and another battery.
A covertway and glacis were also located close to the land front, but were mostly cleared away in the 19th century.

Birgu had four city gates, three of which still survive.
They were designed by Charles François de Mondion in the 18th century, and are in the Baroque style:
Couvre Porte Gate – the first of the three main gates, located within the west side of Couvre Porte Counterguard.

Advanced Gate – the second of the three main gates, located on the right face of St. John Bastion.

Gate of Provence – the third and last of the three main gates, located on the inner flank of St. John Bastion.

Porta Marina – a gate located on the western extremity of Birgu.
It was destroyed in the explosion of 1806.
The present layout of Birgu's fortifications is mainly a result of the 18th century rebuilding by the French architect Charles François de Mondion, although the general layout dates back to the mid-16th century. The fortifications consist of (listed going clockwise from Fort St. Angelo to Dockyard Creek):
Fort Saint Angelo – a large bastioned fort, originally a castle built in or before the 13th century, modernized between the 16th and 17th centuries by the Order of Saint John. The present layout dates back to a major reconstruction by Flemish architect Carlos de Grunenbergh in the 1690s. For more details about the fort's layout, see here.
An irregular enceinte, beginning from the moat of Fort St. Angelo and ending at the Post of Castile. Its northern end was occupied by a battery, now partially dismantled.
Post of Castile (Maltese: Il-Prexxa, Italian: La Breccia) – the east extremity of the Birgu Land Front. It was originally built before 1565 and played a crucial role in the Great Siege. The present layout dates back to the 18th century, and consists of a retrenchment and a hornwork.
St. James Bastion – a two-tiered pentagonal bastion built prior to 1565 and redesigned by de Mondion in the 18th century. Part of the original 16th century bastion was rediscovered during restoration works.
St. James Cavalier – a small pentagonal cavalier built on St. James Bastion sometime in the 18th century.
French Curtain – a curtain wall linking St. James and St. John Bastions.
St. John Bastion – a large asymmetrical bastion containing two of the three main gates of Birgu, designed by de Mondion in the 18th century. A modern road passes through an arch in the bastion.
St. John Cavalier – a two-tiered cavalier built on St. John Bastion. It was originally built prior to 1565, but was modified in the 18th century. Minor alterations were also made by the British in the 19th century.
Couvre Porte Counterguard – a pentagonal counterguard built to protect St. John Bastion. It was built during the reign of Antoine de Paule, and was modified in the 18th and 19th centuries. The British developed its casemates into a barracks, which now houses the Malta at War Museum.
A curtain wall linking St. John Bastion to Dockyard Creek. Originally there was a small bastion but this was destroyed in the explosion of 1806.
The entire land front is surrounded by a rock-hewn ditch, which also includes a caponier and another battery. A covertway and glacis were also located close to the land front, but were mostly cleared away in the 19th century.
Birgu had four city gates, three of which still survive. They were designed by Charles François de Mondion in the 18th century, and are in the Baroque style:
Couvre Porte Gate – the first of the three main gates, located within the west side of Couvre Porte Counterguard.
Advanced Gate – the second of the three main gates, located on the right face of St. John Bastion.
Gate of Provence – the third and last of the three main gates, located on the inner flank of St. John Bastion.
Porta Marina – a gate located on the western extremity of Birgu. It was destroyed in the explosion of 1806.
Fortifications of Birgu