An eccentric collection of artefacts awaits at this museum in a former coastguard station on a grassy verge right by the waterfront. The most fascinating exhibits are from the sunken wrecks of Lough Foyle, the displays exploring the demise of the Spanish Armada and the examples of Drontheim fishing boats, once widely used along Ireland's north coast. There's also an astronomy show in the full-dome digital theatre at the Planetarium.
A welcoming cafe with tables out the front is right next door. If the sun's out, grab a coffee and savour the harbour views.