The Circular Walls are of an elliptic form and enclose the summit of a high hill called Monte Ale which dominates the surrounding hills and plains.  The village is of modest dimensions and could never enjoy an expansion due to the bad condition of its walls that perpendicularly measure only 570 metres.  The main diameter of the castle is of 172 metres and the thickness of the walls is of 2 metres.

The Church of Monteriggioni is a small parish church built in 1219 and named S. Maria Assunta.  It is made up of a single very wide nave covered with vaults closely-fitted to the ceiling’s trusses.  The nave ends with a square apse having the gothic-styled cross-vaults.  Behind the main alter there is a ligneous choir which dates back to the XVI century. The façade is polychromatic and built from travertine lime and “pietra serena”.  Above it, there is a big portal overlapping an archivolt which has an eye with decorations in brick. 

Monteriggioni  is the typical example of a fortified village; a small town of 42 inhabitants surrounded by circular walls.  Inside the walls are the houses of the inhabitants, two bars, a mini-market, two restaurants, a souvenir shop, an “erboristeria”, a hotel and a place selling typical Monteriggioni products.

The towers rise above the walls by 6.5 metres and have a thickness of 4x6 metres.  In the middle ages, their height was of 15 metres.  The original number of the towers was 15 but now the only visible ones are 11 and they are those that tower over the walls.  The other 4 are of the walls’ height.  There was a passage-way at the top of the walls that enabled guards to walk round the circular walls.         

The bell-tower was built in the XVIII century by the pievese Mecacci who according to tradition used material from the old church of S. Giovanni a Stecchi.  The inside of the church contains:

--- 2 Tabernacles dating back to the XV century

--- A Painting of La Madonna del Vanni

--- A Ligneous crucifix

--- A Bell dating back to the year 1298 donated by the Republic of Siena.

Piazza Roma is at the entrance to the Castle: after having crossed the main gate to the castle and walked along a little street, one comes into view of a big piazza – Piazza Roma.  This piazza is the main piazza of the Castle and despite having the characteristics of Tuscan villages it also makes one think of the countryside due to the vegetation of its surrounding fields and gardens and especially of the green lawn between the paved.