I recently spent some time Malta. A unique feature of the Maltese architecture is the tradition of statute niches found on the exteiror walls and corners of buildings.
Some of the niches are covered while others are free-standing. The statues that they contain also come in a variety of sizes and generally depict Christ, the Blessed Virgin or the saints, while some show the souls of purgatory.
Valletta the capital city of Malta has a large number of corner niches, many of which were built in the 16th century during the rebuilding of the capital by the Order of the Knights of Saint John.

Niches serve several functions. Firstly, they offer the opportunity for faithful to express their beliefs in public. The locals decorate these niches with flowers and lit candles (Camilleri 2015, 24).

According to A Taste of Maltese Folklore
Another function is that of providing a familiar landmark to locals. Whenever someone wishes to meet another person, they would often decide on a particular niche as a meeting place, as this would be well known by the locals (Camilleri 2015, 24).
Many of the statues are associated with a plaque that details the
… number of days’ indulgence granted to those who stop for a while to offer a prayer (Camilleri 2015, 24).

I also noticed a number of niches that contained paintings or religious images. Below is an elaborate wall plaque from a street in Valletta. I forgot to make note of the street name. Above the plaque is the date 1752.

I came across another at Lvant in Valletta, with a a plaque and small altar filled with fresh flowers underneath.
I noticed a similar one at Sliema with three alters filled with fresh flowers beneath the image of the Blessed Virgin at Sqaq Guaz Fava.
So if you ever make it to Malta make sure you keep your eyes pealed for these wonderful statue niches.
References
Camilleri. J. C. 2015. A taste of Maltese Folkore traditions and heritage. BDL Publishing.