The last time we were in Thessaloniki was in 2008 and I don't think the Forum, and its underground Museum, was open to visitors then.
1
The Roman Forum dating from the late 1st century A.D.
It looks as if, after the excavations finished, the surrounding banks were covered with plants to stabilize the earth.
Some plants were more successful than others
2
The Odeon
Now used for open air events.
The wide open space of the Forum has been sown with grass. Solanum elaeagnifolium, Germanos has invaded this area
3 & 4
The underground Stoa
The entrance to the Stoa and some dandelion like plants
The Stoa entirely plant free