On a very low tide (<1.3m) it's possible to walk out across the mudflats from Town Beach to the wrecks of Catalina and Dornier flying boats attacked by Japanese 'Zeroes' during WWII. The planes had been evacuating refugees from Java and many still had passengers aboard. Over 60 people and 15 flying boats (mostly Dutch and British) were lost. Only six wrecks are visible, with the rest in deep water.
Start walking an hour before low tide and head roughly southeast for 1.5km (about 30 minutes). Wear appropriate footwear – the mud's sticky and can hide sharp objects, not all of them inanimate. Watch out for other marine hazards like jellyfish and check with the visitor centre for tide times. The museum also has a handy brochure. Or just take the hovercraft.