Eiffel Tower

Yes, and earlier than most people expect. Entry is by timed slot and the official releases sell out well ahead, particularly for the summit and for evening times. Arriving without a slot means the walk-up queue, which is the slowest possible way in and can consume most of an afternoon in season. If the lift tickets are gone, the stairs to the second level are usually still available and are a better experience than queueing.

The second level, for most visitors. It is high enough to read the whole plan of Paris and low enough to still recognise individual buildings, streets and bridges, which is what people actually want from the view. The summit at 276 metres is about altitude rather than detail — the city flattens out from there, and the platform is smaller and more crowded. The summit also closes in high wind. If you are choosing one, take the second level; if the weather is hazy, take it without hesitation.

Yes, as far as the second level. It is over three hundred steps from the ground to the first level and roughly as many again from the first to the second, so around six hundred in total, on an open staircase inside the ironwork. It is a genuinely good way to see the structure close up and the tickets are cheaper and easier to get on short notice. The summit is reachable only by lift from the second level, so stair climbers who want the top buy an upgrade when they get there.

The Trocadéro terrace across the Seine, for the straight-on full-height frame that most people have in mind — go early, because it fills. The Champ de Mars on the other side gives a softer, greener foreground and better late-afternoon light. And standing directly underneath and shooting straight up through the lattice gives a completely different photograph that costs nothing and needs no ticket. One note: the tower’s night illuminations are protected, so images of the lit tower are fine for personal use but not automatically for commercial use.

Two to three hours from arriving at the security perimeter to leaving, if you have a timed slot. That covers screening, the lift up, time on the first and second levels and the descent. Add roughly an hour if you are also going to the summit, and more in peak season when every stage has a queue of its own. If you only want the photograph rather than the ascent, half an hour at Trocadéro does it and needs no ticket at all.

Because it was never meant to be permanent. The tower was built as the centrepiece of the 1889 Exposition Universelle on a concession that would have seen it dismantled about twenty years later, and a great deal of artistic Paris signed a public protest against it while it was still going up. What saved it was usefulness rather than affection: a very tall iron structure in the middle of the capital turned out to be extremely valuable for radio telegraphy, and by the time the concession expired the tower had become part of the country’s communications infrastructure. It was listed as a monument historique in 1964 and has been part of the UNESCO "Paris, Banks of the Seine" inscription since 1991.