Photo taken on July 28, 2019 shows the entrance of Tito's Cave on the Island of Vis, Croatia. Tito's Cave is a shelter located beneath the Mountain Hum on the Island of Vis. It was used by former Yugoslavian leader Tito in 1944 to hide from Nazi troops. (Dalibor Urukalovic/Pixsell via Xinhua)

Tourists vist Tito's Cave on the Island of Vis, Croatia, July 28, 2019. Tito's Cave is a shelter located beneath the Mountain Hum on the Island of Vis. It was used by former Yugoslavian leader Tito in 1944 to hide from Nazi troops. (Dalibor Urukalovic/Pixsell via Xinhua)

Tourists vist Tito's Cave on the Island of Vis, Croatia, July 28, 2019. Tito's Cave is a shelter located beneath the Mountain Hum on the Island of Vis. It was used by former Yugoslavian leader Tito in 1944 to hide from Nazi troops. (Dalibor Urukalovic/Pixsell via Xinhua)

Tourists vist Tito's Cave on the Island of Vis, Croatia, July 28, 2019. Tito's Cave is a shelter located beneath the Mountain Hum on the Island of Vis. It was used by former Yugoslavian leader Tito in 1944 to hide from Nazi troops. (Dalibor Urukalovic/Pixsell via Xinhua)

Photo taken on July 28, 2019 shows a fort outside Tito's Cave on the Island of Vis, Croatia. Tito's Cave is a shelter located beneath the Mountain Hum on the Island of Vis. It was used by former Yugoslavian leader Tito in 1944 to hide from Nazi troops. (Dalibor Urukalovic/Pixsell via Xinhua)