Žižkův dub, Ancient oak tree in Třemošnice, Czech Republic.

Žižkův dub is a hollow-trunked summer oak standing by the former castle road in Podhradí, part of Třemošnice near Lichnice Castle. Its open cavity is roofed at the top where the old terminal once grew, and its girth of 890 to 922 cm places it among the five most massive memorial oaks in the Czech Republic.

The oak dates to around the 13th century, appearing during the founding period of nearby Lichnice Castle. Since then it has witnessed the military conflicts and changes that shaped this part of the Czech landscape.

The oak is called Žižkův after two Hussite campaigns against Lichnice Castle, though Jan Žižka took part in neither. A plaque on the trunk reads: "I have stood here by the old castle road for over 600 years. I saw the castle built, its glory, siege and fall."

The tree stands in the Podhradí area and is accessible via marked walking paths through the countryside. The location is open and unobstructed, allowing you to view the entire monument from different angles.

The hollow trunk was once lined with masonry, a treatment later found to block natural ventilation and regeneration. Conservationists from Třemošnice and the Železné hory protected landscape area removed the brickwork and capped the cavity instead.