Old Royal Naval College in Greenwich

You're standing at the Old Royal Naval College in Greenwich, on the south bank of the Thames. Have a look around. Four grand buildings with two domes are laid out in a neat pattern, with a wide open avenue running down the middle. Look along that avenue to the south. There's the white Queen's House, and behind it the park, the hill and the Royal Observatory. That view is no accident. Architect Christopher Wren, the man behind St Paul's Cathedral, first drew up plans that would have blocked the Queen's House's view of the river. Queen Mary II considered that a real blunder, so the complex was split in two. The gap is exactly as wide as the Queen's House itself.