Paris Montparnasse – Top of the city

This guide to the Montparnasse observation deck in Paris covers the 1973 opening of the tower beneath your feet, once the tallest building in France and almost instantly one of its most hated, ranked among the world's ugliest in a 2008 poll. It traces how the backlash pushed Paris to ban skyscrapers from its centre and what stood on this site before the tower rose, a Victorian train hall that served Brittany and the Atlantic coast for a century. Take a slow circuit of the rooftop rail to pick out Sacré-Cœur, the Eiffel Tower and Notre-Dame from up here.