Arch of Sea Ports (Arco da Portas do Mar) is situated at Rua dos Bacalhoeiros, facing the River Tagus

Arch of Sea Ports (Arco da Portas do Mar) is situated at Rua dos Bacalhoeiros, facing the River Tagus

This 3.7m wide and 9m long, serves as a link between the street of Bacalhoeiros and Afonso Street Albuquerque

This 3.7m wide and 9m long, serves as a link between the street of Bacalhoeiros and Afonso Street Albuquerque

Arc of Portas do Mar once was a Muslim watchtower  in the medieval walls of Lisbon

Arc of Portas do Mar once was a Muslim watchtower in the medieval walls of Lisbon

Close to Chafariz Del Rey on R. Cais de Santarém lies this door

Close to Chafariz Del Rey on R. Cais de Santarém lies this door

Looking at the inner side of the arch - there is a strong possibility that this door (arch) was built between two towers of the wall

Looking at the inner side of the arch - there is a strong possibility that this door (arch) was built between two towers of the wall

Very close to this door, there is a19th-century mansion with a Muslim facade, named Palacete Chafariz D'El Rei

Very close to this door, there is a19th-century mansion with a Muslim facade, named Palacete Chafariz D'El Rei

Stairs lead from Rua de Sao Joao da Praca through Arco de Jesus to Rua Cais de Santarem

Stairs lead from Rua de Sao Joao da Praca through Arco de Jesus to Rua Cais de Santarem

This arch like structure was once part of Lisbon's defensive system - Over the centuries, many new arches or doors were opened to provide access to Alfama district

This arch like structure was once part of Lisbon's defensive system - Over the centuries, many new arches or doors were opened to provide access to Alfama district

This is one of the oldest doors in Lisbon, during the Muslim period it was called Bab al-Madiq

This is one of the oldest doors in Lisbon, during the Muslim period it was called Bab al-Madiq

Arco de Jesus, seen from Rua Cais de Santarem - this arch provided an access between the beach and the inner city

Arco de Jesus, seen from Rua Cais de Santarem - this arch provided an access between the beach and the inner city

Situated at Rua da Alfandega (close to Arco de Jesus) is the Wicket of the Marquis of Lavradio (Postigo do Marques do Lavradio)

Situated at Rua da Alfandega (close to Arco de Jesus) is the Wicket of the Marquis of Lavradio (Postigo do Marques do Lavradio)

This small gate was opened to serve the Palace of Marquis of Lavradio in the 17th century - this door was also used by the public

This small gate was opened to serve the Palace of Marquis of Lavradio in the 17th century - this door was also used by the public

Preguica Arch (Arco da Preguica) is known to have existed from the 15th century (atleast)

Preguica Arch (Arco da Preguica) is known to have existed from the 15th century (atleast)

It was opened to allow access to the Fonte Nova (the new Fountain), just outside the city walls

It was opened to allow access to the Fonte Nova (the new Fountain), just outside the city walls

In the 16th century, this water supply source was known as Fonte Nova de Porta do Mar (the New Sea Gate Fountain) or Fonte de Preguica, hence the name suggests

In the 16th century, this water supply source was known as Fonte Nova de Porta do Mar (the New Sea Gate Fountain) or Fonte de Preguica, hence the name suggests

In 1755, this arch was known as Arco da Conceicao (Arch of the Conception)

In 1755, this arch was known as Arco da Conceicao (Arch of the Conception)

At Rua da Saudade, close to Museu do Teatro Romano, there is a large chunk of a wall like structure

At Rua da Saudade, close to Museu do Teatro Romano, there is a large chunk of a wall like structure

Looking at its foundations, it gives a hint that it might had been part of the city wall extending all the way to the Castle of San Jorge

Looking at its foundations, it gives a hint that it might had been part of the city wall extending all the way to the Castle of San Jorge

One of the most famous doors of Lisbon was Porta do Sol (Bab al-Maqbara in Arabic)

One of the most famous doors of Lisbon was Porta do Sol (Bab al-Maqbara in Arabic)

Steps beside the walls at Porta de Sol - this door is facing east, close to the Museum of Decorative Arts

Steps beside the walls at Porta de Sol - this door is facing east, close to the Museum of Decorative Arts

Igreja de Santa Luzia (Church of Santa Luzia) sits at the top of the remains of the door

Igreja de Santa Luzia (Church of Santa Luzia) sits at the top of the remains of the door

During the Muslim period, a cemetery had existed here, hence the name (Bab al-Maqbara) later it was called Almocavar

During the Muslim period, a cemetery had existed here, hence the name (Bab al-Maqbara) later it was called Almocavar

Sections of Lisbon's medieval wall can be seen at Rua Judiaria

Sections of Lisbon's medieval wall can be seen at Rua Judiaria

This appears to be the remains of a watchtower and at the top of it there is a house with a small garden

This appears to be the remains of a watchtower and at the top of it there is a house with a small garden

A closer look at the section of the wall at Rua Judiaria

A closer look at the section of the wall at Rua Judiaria

A small fountain at the Rua Judiaria - this is the area where Jews of Lisbon lived during the Muslim period

A small fountain at the Rua Judiaria - this is the area where Jews of Lisbon lived during the Muslim period

When wondering around in the Alfama district, it is easy to forget that this is part of LIsbon due to its narrows streets and Moorish influence

When wondering around in the Alfama district, it is easy to forget that this is part of LIsbon due to its narrows streets and Moorish influence

This small street leads to Largo do Terreiro do Trigo, facing the River Tagus

This small street leads to Largo do Terreiro do Trigo, facing the River Tagus

An old stone seemed to get caught in between the newer wall

An old stone seemed to get caught in between the newer wall

And another section of the wall is surrounded by graffiti

And another section of the wall is surrounded by graffiti

There are signs beside the old doors and arches of Lisbon but finding them all is not an easy task

There are signs beside the old doors and arches of Lisbon but finding them all is not an easy task

Couraca ( a double wall) was built here which connected the tower of Saint Peter to the walls' perimeter

Couraca ( a double wall) was built here which connected the tower of Saint Peter to the walls' perimeter

It is believed that this wall was built around 14th century as part of the Fernandine wall (1373-1375)

It is believed that this wall was built around 14th century as part of the Fernandine wall (1373-1375)

It has a small gate (wicket) for pedestrians - its walling up was done in 1650 due to the threat of a Castilian invasion

It has a small gate (wicket) for pedestrians - its walling up was done in 1650 due to the threat of a Castilian invasion

Poet's Fountain (Fonte do Poeta) at Rua da Judiaria, a sign beside the fountains says ' this fountain is just fixed, please don't damage it'

Poet's Fountain (Fonte do Poeta) at Rua da Judiaria, a sign beside the fountains says ' this fountain is just fixed, please don't damage it'

A tower like structure, it is hard to tell if it played any defensive role in the past or it is just a part of a house

A tower like structure, it is hard to tell if it played any defensive role in the past or it is just a part of a house

Looking back at the tower of the Saint Peter and the door which used to exist here

Looking back at the tower of the Saint Peter and the door which used to exist here

Another photo of the wicket of Marquis of Lavradio

Another photo of the wicket of Marquis of Lavradio

Wall of the Porta do Sol on a sunny day

Wall of the Porta do Sol on a sunny day

This part of the medieval door has a terrace (at upper and lower levels) which is a magnet for the tourists to have the wonderful views of the River Tagus

This part of the medieval door has a terrace (at upper and lower levels) which is a magnet for the tourists to have the wonderful views of the River Tagus

During the Islamic period this (Porta del Sol) would have provided entry in the medina

During the Islamic period this (Porta del Sol) would have provided entry in the medina

Two patios D. Fradique of Up and Down - this is the beginning of the longest wall (86m)

Two patios D. Fradique of Up and Down - this is the beginning of the longest wall (86m)

A sign sits in the middle with the area around it where two towers had existed

A sign sits in the middle with the area around it where two towers had existed

This section of the wall is stretched from the Belmonte Palace to the Azurara Palace

This section of the wall is stretched from the Belmonte Palace to the Azurara Palace

These towers were integrated into the Belmont Palace in the 16th century

These towers were integrated into the Belmont Palace in the 16th century

Accounts from the 1147 conquest of Lisbon suggest that in this area, part of the wall was destroyed by the crusaders

Accounts from the 1147 conquest of Lisbon suggest that in this area, part of the wall was destroyed by the crusaders

Old Islamic tower had existed here, between the towers, there was an arched passageway

Old Islamic tower had existed here, between the towers, there was an arched passageway

Probably, it was opened during the medieval times to allow access to the eastern suburbs

Probably, it was opened during the medieval times to allow access to the eastern suburbs

This is an open area in the Largo Porta del Sol on the street with the same name

This is an open area in the Largo Porta del Sol on the street with the same name

This cafe/bar is built in the old watchtower, a sign with the name can be seen to the right

This cafe/bar is built in the old watchtower, a sign with the name can be seen to the right

Just at the back of this tower lies the Museum of Decorative Arts

Just at the back of this tower lies the Museum of Decorative Arts

I was told by the reception that this tower now houses craftsmen which can be visited for a steep fee

I was told by the reception that this tower now houses craftsmen which can be visited for a steep fee

A section of the medieval wall is also found in the Casa dos Bicos

A section of the medieval wall is also found in the Casa dos Bicos

Old Muslim walls of Lisbon had existed here in the past but they were demolished to make way for this house

Old Muslim walls of Lisbon had existed here in the past but they were demolished to make way for this house

These two structure are one of the best examples of the city's defensive system found inside the Casa dos Bicos

These two structure are one of the best examples of the city's defensive system found inside the Casa dos Bicos