If you are accosted by a boatload of horned-helmeted Vikings when strolling Dublin's streets, do not be alarmed.

BBC: Dublin's Viking heritage

If you spot a Welsh MP poring over a large map today, do not be alarmed.

BBC: Maps, maths and boundary changes - MPs digest details

Thousands of American tourists, clogging Washington's streets in search of cherry blossom, have every reason to be alarmed - except they do not seem to be.

BBC: By BBC Washington Correspondent Stephen Sackur