Arrangements for these need to be considered long in advance, as bookings may be needed more than a year ahead of time.

The General Assembly has expressed very strongly the view that "on-site" accommodation (i.e., in student residences) is to be preferred to hotels wherever possible, in that even if it is less luxurious, it is cheaper, more convenient, and leads to much greater scientific and social contact. Anyone who wishes to opt for a hotel is of course then at liberty to do so. Where student accommodation is not available, it is necessary to ensure that the local hotels are prepared to carry the load, and adequate information, notice and advice must be given to intending participants. Many cities now have some form of Conventions Bureau, or Tourist Office, to help with hotel bookings. Transport may also have to be provided to and from hotels, if large distances are involved.

Information about local camping sites should be included in the second circular, because some participants use this as a way of keeping costs down.

As regards meals, student facilities are again generally the most satisfactory solution where possible. But however the catering is done, it is essential to check that the system can cope with over 200 people simultaneously requiring the same meal (the same considerations apply to the serving of coffee in breaks between sessions). Remember also that many participants will need a meal on the Monday evening.

Two main lecture theatres will be needed; one must be able to hold all the participants (say 250-300, to be safe), for plenary sessions; the other should take at least 150 for the occasions when parallel sessions are run. The theatres should be sufficiently close together for people to be able to move from one parallel session to the other without undue inconvenience. If Poster Sessions are to be held, a further room (or possibly corridor) is required, the size depending on the number of contributions. Ideally plenty of free space for circulation should be available. Coffee or tea should be provided between sessions, again not too far from the lecture theatres.

It is also convenient if there is somewhere close by where people can sit and talk while sessions are in progress.