This is a list of websites relevant to lichens, or to Greek natural history, or to other Greek topics that you may find of interest. If you know of other sites that I ought to include, please let me know.
The website of the British Lichen Society is a good starting point for beginners. If you want to learn more about lichens, consider joining the British Lichen Society. Membership is open to everyone: you don't have to be British.
Dr. H. J. M. Sipman maintains a site with photos of many species that occur in the Aegean, i.e. a significant proportion of the Greek species. (Information on that site is reliable, but take care if you use photographs from other sites. Many photographs of lichens that you will find online are incorrectly identified.)
Good information is hard to come by
There is a nice site about the island of Thasos
If you are in Athens during the summer, and have an evening to spare, visit the Dora Stratou dance theatre for an outstanding performance of traditional Greek dance. The open air theatre is only 15 minutes walk from the Acropolis. Performances are 9pm to 1030pm, Wednesday to Sunday, throughout the summer months. Tickets are 15 euros. If you want to learn more about the large and fascinating subject of traditional Greek dance, start here, or ask me.