Imagine the gaping hole in the Parisian skyline (and our hearts) if all 18,000 metal parts of Gustave Eiffel’s jaw-dropping monument had been taken down at the end of the 1889 World Fair as originally planned. Thankfully, this elegant Parisian icon is still standing and poised for selfie opportunities galore. You can ascend to different levels of the 300-metre structure – though bear in mind the very utmost part is closed at certain times of the year. When it's open though, there's a cosy salon up there to gaze at the whole of Paris from. Be sure to check the tower from afar in the evening too, when for ten minutes on-the-hour 20,000 flashbulbs light the tower.