Portland Castle
... that the heart of Portland Castle is the keep, comprising a central tower with two wings on either side and a gun battery to the front?
... that the heart of <b id="mwgg"><a href="./Portland_Castle" id="mwgw" rel="mw:WikiLink" title="Portland Castle">Portland Castle</a></b> is the <a href="./Keep" id="mwhA" rel="mw:WikiLink" title="Keep">keep</a>, comprising a central tower with two wings on either side and a gun battery to the front?