Be clear on this, because the name misleads. The Austrian National Library is a working national library across several buildings. What visitors come to see is one room within it: the Prunksaal, or State Hall.

It is a baroque library hall built for Emperor Charles VI in the early eighteenth century — around eighty metres long, with a frescoed central dome, walnut shelving, marble columns, statues of Habsburg emperors and roughly two hundred thousand books from the period.

There are also four monumental Venetian globes, two terrestrial and two celestial, standing in the hall.

That is the visit. It is one room, and it is enough.

The library also runs smaller museums elsewhere in the complex — a papyrus museum, a globe museum, an esperanto museum — each with its own ticket.

The only expectation worth setting. This is not a museum you walk through for two hours. It is a single hall, you enter at one end, and you look.

A small number of visitors feel the ticket is steep for a room. The overwhelming majority describe it as one of the most beautiful spaces they have ever stood in and consider it money well spent.

A rotating exhibition occupies display cases down the centre of the hall, which adds some content and changes through the year.

Allow half an hour to forty-five minutes. Go slowly, look up at the dome, walk both ends, and look at the globes properly.

If you photograph it and leave in five minutes, it will feel expensive. If you stand still in it, it will not.

Inside the Hofburg complex, on Josefsplatz, which is a courtyard square on the southern side of the palace.

The entrance is up a staircase from the square, and it is easy to walk past — several visitors report circling the Hofburg looking for it.

It is a separate ticket from everything else in the Hofburg. The Imperial Apartments ticket does not include it, and vice versa.

Josefsplatz itself is one of the finest squares in Vienna and worth a moment even if you do not go in.

The Albertina is a two-minute walk away, and the Spanish Riding School is adjacent, which makes a natural cluster for a morning.

Tickets are bought at the door or online, and queues are rarely a problem — this is one of the quieter major sights in Vienna.

Combination tickets link the State Hall with the library’s other small museums, and Vienna city passes include it.

The library is closed one day a week and has limited hours on some days, which catches people out. Check before you go.

A short guided tour is sometimes available and adds context that the room does not supply on its own.

Prices change periodically, so check the official site rather than any figure quoted elsewhere.

Photography without flash is permitted, and this is one of the most photographed interiors in Europe.

The difficulty is dynamic range: the room is dim, the windows are bright, and phone cameras struggle. Expose for the shelving rather than the windows, brace against a balustrade, and accept that the dome fresco needs a steady hand.

The classic shot is down the length of the hall from one end, with the dome in the upper third.

The globes photograph well close up.

Tripods are generally not permitted. Early in the day gives you the emptiest room.

Early is best, as everywhere, but this is a comparatively quiet site and the difference is smaller than at the palaces.

Morning light through the tall windows is the best of it.

The room fills briefly when a tour group arrives and empties again within twenty minutes, so if it is crowded when you enter, wait rather than leaving.

Check the closing time, which is earlier than the major museums, and note the weekly closing day.

In December the room is decorated and the exhibition often has a seasonal theme.

December and September are the busiest months here, with July and August close behind.

January and February are the quietest.

Being a single indoor room, the season affects only the crowd and the light.

Winter light is short but the interior is artificially lit and atmospheric.

This is a good rainy-day option in a city that has plenty of them, and it slots easily into an hour between other things.

The State Hall is reached by a staircase from Josefsplatz, and access arrangements for wheelchair users exist but are not obvious — contact the library in advance rather than arriving and hoping.

Once inside, the hall itself is a single level and easy to move around.

There is limited seating in the room.

The surrounding Josefsplatz is level and cobbled.

Given the short duration of the visit, this is a manageable stop for most visitors, but the access route is worth confirming first.

There is almost no criticism of this room in the reviews beyond the price for a single hall.

The thin version: buy a ticket, take three photographs, leave in five minutes, and feel it was expensive.

The good version: go early, walk the full length twice, sit if you can, look properly at the dome fresco and the globes, read the exhibition in the cases, and understand that you are standing in the finest baroque library interior in the world.

Half an hour, one room, and one of the things people remember longest from a trip to Vienna.