fire baskets
... that fire baskets were once used to mark the main route through Danish waters from the North Sea to the Baltic?
... that <b id="mw_g"><a href="./Fire_basket" id="mw_w" rel="mw:WikiLink" title="Fire basket">fire baskets</a></b> were once used to mark the main route through Danish waters from the <a href="./North_Sea" id="mwAQA" rel="mw:WikiLink" title="North Sea">North Sea</a> to the <a href="./Baltic_Sea" id="mwAQE" rel="mw:WikiLink" title="Baltic Sea">Baltic</a>?