Agia Theodora (Church of Holy Virgin Martyr Theodora) is a small Byzantine church with 17 trees - 200 years old - growing on its roof; most of them are taller than 20 metres. Only one single root can be seen above the entrance. No roots can be seen anywhere else, not even inside the church. The walls are 70 cm thick. Underneath the church is the source of a river whose water feeds the trees. Inhabitants of the region have built the church in the 12th century.

Nowadays the church is a popular place of pilgrimage. Believers are said to have received numerous miracles. In 1965 the church was declared a monument.

Theodora grew up in Vasta, where the family would send the sons to fight in the army against the enemy. Having no boys in the family, Theodora decided to join the army to save her father from having to do so. Disguising herself as the soldier Theodore, she soon became one of the most valiant and brave soldiers. A woman soon developed lustful feelings for “Theodore” and claimed that he had impregnated her. Theodora was commanded to either marry the woman or be condemned to death. Doing nothing to prove her innocence (as easy as this would be) Theodora placed her hope in God.

Being condemned to death, before her execution, she prayed, “Let my body become a church, my blood a river, and my hair the trees.” On the spot where she was martyred, a spring gushed forth which flooded to become a river which still exists today. The 17 trees on the roof of the church are symbolizing Theodora's age at the time of death.