
Pula Arena
One of the world's best-preserved Roman amphitheatres.
Photo: Olgierd Rudak / CC BY-SA 4.0

Photo: Wikimedia Commons / CC BY-SA
Set inside the 19th-century Fort Verudela, this aquarium fills the old gun casemates with the life of the Adriatic: from seahorses and rays to a whole room of Mediterranean species. On the ramparts above sits its marine-turtle rescue centre, where injured loggerheads recover before being released back to sea.
Don't skip the rooftop: the sea-turtle rescue pools and fort views are the best part.
A small next-step selection from the same city.

One of the world's best-preserved Roman amphitheatres.
Photo: Olgierd Rudak / CC BY-SA 4.0

Tito's island paradise of dinosaurs and safari.
Photo: Wikimedia Commons / CC BY-SA 4.0

A cool maze of WWI tunnels beneath the city hill.
Photo: Psittacuso / CC BY-SA 4.0
Use the free map from home, then verify the discovery when you reach the place.