Natural History Museum

General admission costs nothing and always has. There is no ticket to buy for the permanent galleries.

What the museum asks at busy periods is that you reserve a free timed slot online. It is not compulsory, and visitors without one report waiting only ten minutes on a quiet day — but in school holidays and at weekends the queue runs from the museum back toward the Underground station.

Booking takes two minutes and costs nothing, so there is no reason not to.

Donations are invited rather than required.

What is not free: the major temporary exhibitions and the ice rink in winter, which are separately ticketed and sell out.

The detail that saves the most time and almost nobody knows.

The main entrance on Cromwell Road is the grand one, with the steps and the Romanesque facade, and it carries the heaviest traffic and the longest security queue.

The Exhibition Road entrance, round the side, is frequently much quicker and brings you in at a different level of the building.

There is a bag check at both.

If you arrive by Underground at South Kensington, the pedestrian subway tunnel runs directly from the station toward the museums — convenient in rain, and congested at peak times.

On a busy day, walking the extra three minutes to Exhibition Road is worth it.

The entrance hall is the reason people photograph this museum before seeing a single exhibit.

A blue whale skeleton hangs suspended from the ceiling of a vast Romanesque hall of terracotta arches, staircases and carved animals worked into the stonework. The whale replaced the diplodocus cast that occupied the space for decades.

Look at the building as well as the skeleton. The terracotta is covered in modelled plants and creatures — extinct species on one side of the hall, living ones on the other, which was the Victorian designer’s deliberate scheme.

The upper balconies give the best view down onto the whale and are much quieter than the floor.

This room alone justifies walking in, and it costs nothing.

The most popular gallery in the building and the reason a large proportion of families come.

The gallery runs along a raised walkway above the specimens, ending with an animatronic T. rex, and it is the single most congested space in the museum.

Expect a queue to enter it at peak times, and expect it to be slow-moving once inside because the walkway is narrow and one-directional.

Go first thing or late in the day. Mid-morning through mid-afternoon in school holidays is the worst of it.

If the queue is impossible, the mammals gallery with its own life-size blue whale model is a good substitute and is almost always walkable.

The museum is organised in colour-coded zones and is far too large for one visit.

The mammals gallery with the suspended blue whale model. The earthquake simulator in the red zone. The Darwin Centre cocoon, holding part of the research collection behind glass with scientists visibly at work.

The minerals gallery is a Victorian room almost unchanged since it opened — long cases, wooden cabinets, and the vault holding meteorites and gemstones.

The wildlife garden outside is free and seasonal.

Pick two zones rather than attempting the building. Visitors who try to see everything describe exhaustion; those who chose describe a good morning.

Two related complaints that recur.

The building has limited air conditioning, and on a warm day with a full house the galleries become genuinely uncomfortable. Reviewers use the word tiring rather than merely warm.

The crowding is concentrated: the Hintze Hall, the dinosaurs and the route between them carry most of the traffic. Step into the minerals gallery or the quieter corners of the green zone and the building relaxes considerably.

The practical response is timing. First thing in the morning, or the last ninety minutes before closing, are materially different experiences from the middle of the day.

School term-time weekday mornings are quieter than anything in the holidays.

August is by far the busiest month, with July close behind — this is a family attraction and it follows the school calendar.

January, March and November are the quietest.

Within the day, be there at opening. The first hour is the only reliable way to see the dinosaur gallery without queueing for it.

Late afternoon empties as families leave.

Rainy days fill every free museum in London simultaneously, so a wet August afternoon here is the worst combination available.

The museum is closed for a few days around Christmas.

One of the best family days in London and it is free, which is a rare combination.

What works: the dinosaurs above all, the blue whale, the earthquake simulator, the creepy-crawlies gallery, and the sheer scale of the building.

There are family trails and activity backpacks — ask at an information desk.

The constraints are crowding and stamina. Two zones, a break in the middle, and out before anyone melts down is a better plan than a full circuit.

Pushchairs are fine with lifts throughout, though the dinosaur walkway is tight.

The Science Museum next door and the V&A opposite are both free, which makes this corner of South Kensington a three-day proposition if you wanted.

There are cafés and a restaurant in the building, priced as museum catering is, and they are busy at lunchtime.

You may bring your own food, and there is a designated picnic area — worth knowing with a family.

The streets around South Kensington station have better and cheaper options a few minutes’ walk away.

Toilets are distributed through the building and queue at peak times.

Cloakroom facilities are available for a charge.

Seating in the galleries is limited relative to the visitor numbers.

Good for a Victorian building. Step-free access is available at the Exhibition Road entrance, lifts serve the public floors, and accessible toilets are provided.

Wheelchairs can be borrowed and should be reserved in advance at busy times.

The crowd density is the genuine barrier rather than the architecture — the dinosaur gallery in particular is difficult in a wheelchair or with a pushchair when busy.

The museum publishes detailed access information and runs quieter early-opening sessions for visitors who need them, which are worth looking for.

An early slot makes more practical difference here than any single facility.

South Kensington on the District, Circle and Piccadilly lines is the nearest station, connected to the museum by a pedestrian subway.

Gloucester Road is a ten-minute walk and is often less congested.

The Science Museum is immediately behind and the V&A directly opposite, both free.

Hyde Park and Kensington Gardens are five minutes north, with the Albert Memorial and the Royal Albert Hall on the far side.

There is no useful parking and the congestion charge applies.

Harrods is a fifteen-minute walk east if that is on the list.

Two to three hours is the realistic figure for a targeted visit covering two zones.

Half a day if you are working through it with children and stopping for lunch.

A full day is possible and is more than most people want.

An hour covers the Hintze Hall and the dinosaurs if the queue cooperates, which is a legitimate short visit.

The practical point: the building is large enough that walking between zones takes real time, and fatigue arrives well before the exhibits run out.

The criticism here is about crowds, heat and queues rather than the collection, and a minority of visitors think it is overrated relative to London’s other free museums.

The frustrating version: turn up at midday in August without a slot, queue outside, queue again for the dinosaurs, walk hot galleries until everyone is tired, and leave having seen a whale and a T. rex.

The good version: book a free slot for opening, come in by Exhibition Road, go straight to the dinosaurs while the gallery is walkable, spend time in the Hintze Hall from the upper balcony rather than the floor, pick one more zone, and be out by lunchtime.

It costs nothing, it is the busiest attraction in the country, and the entire difference is the hour you arrive.