The precourse (Saturday-Sunday) and main workshop (Monday-Friday) will take place at two separate locations that are within 15 minutes walking distance of each other, both in the city center (Berlin-Mitte). See the home page for precise addresses and a map.
Achtung: Do not go to the HU Berlin math department! It is very far away from the actual workshop venues.
By air
One probably new development since the last time you were here (if ever) is that Berlin is now served by a single large airport, called Berlin-Brandenburg International (BER). Do not search for flights to Tegel or Schönefeld, as both of them are no longer being used as airports. (The only reason most people have had to go to Tegel lately is for Covid vaccinations.)
BER is quite close to the former Schönefeld airport and thus technically outside the city, but accessible via public transportation (S-Bahn, regional trains, buses) with a travel time of about 45 minutes to the city center.
Public transportation caveat 1: BER is probably the one place on Berlin's public transportation network for which you will need a ticket that covers zone C. For all other places you are likely to go, tickets for zones A and B suffice.
Public transportation caveat 2: Depending where you are staying, you might be tempted to get to the airport by taking a bus that terminates at "BER Terminal 5". Don't take that bus; "BER Terminal 5" is just a rebranding of the old Schönefeld airport, and it does not run any commercial air traffic. You need to get to BER Terminal 1-2.
Informative complaint: In the subjective opinion of some of the organizers, BER does not function as efficiently as one might hope from a brand new airport. Be sure to get there at least two hours ahead of time when you depart.
By train
Almost all long-distance trains to Berlin stop at Berlin Hauptbahnhof (central station). Many also stop at Bahnhof Südkreuz south of the center, Bahnhof Gesundbrunnen north of the center, and/or Ostbahnhof east of the center; depending on the location of your hotel, one of those other stations may be more convenient for you. All of these stations are connected to the S-Bahn or U-Bahn network.
Public transportation in Berlin is operated by the BVG, which divides the city into three transit zones (A, B and C) and uses a unified ticketing system, i.e. the same tickets are valid on all underground and overground trains (S-Bahn and U-Bahn) as well as public buses and trams (Straßenbahnen). The BVG website includes a very useful journey planner, which will tell you the quickest connection between any two points (stations or addresses) in Berlin. If you like using a smartphone for such purposes, we recommend downloading the free BVG Fahrinfo app for information on routes and schedules, and the BVG Ticket app for buying electronic tickets. (There is also another app called BVG Jelbi that in theory can be used for tickets as well as short term e-scooter and bike rental, but we have observed it to have some annoying bugs.)
(click for a full PDF map of the U-/S-Bahn network)
There are no gates or turnstiles at entrances to stations, but tickets are sometimes checked by plain-clothes control officers riding on trains or trams. On buses, you may be required to show your ticket to the driver upon boarding, and the driver will occasionally pretend to care.
The most commonly needed ticket for individual trips is a single ticket (Einzelfahrschein) Berlin AB: this is good for all travel within zones A and B for up to 2 hours after validation and can be bought for 3.20€ from automated machines in all U- or S-Bahn stations or in trams, from the bus driver (with exact change) when you board a bus, or electronically via the BVG Ticket app mentioned above. If the distance of your trip is at most 3 stations in the U-/S-Bahn network or up to 6 stops on a single bus/tram line, then you can instead buy a Short-trip ticket (Kurzstrecke) for 2.20€. Important: unless you are buying a ticket from a bus driver or buying (typically from a machine) certain kinds of unlimited ride tickets with the period of validity printed on them, all paper tickets need to be validated (entwertet) before you start your journey — this is done by sticking them into validation machines which can be found on every platform or inside buses/trams.
If your accommodation is not within walking distance of Hackescher Markt, then we recommend buying a BVG 7-Day-Ticket (7-Tage-Karte "VBB-Umweltkarte") Berlin AB, which will give you unlimited access to all trains/buses/trams within zones A and B for seven calendar days starting on the day you validate it. This ticket costs 39€ and can be bought from the automated ticket machines in any U- or S-Bahn station (you may have to press a button marked "other tickets" in order to find the option).
Note that almost all important places in Berlin are in zones A or B of the BVG network, including the workshop location, all the hotels on our accommodation list below, and all long-distance train stations. The only major exception is the airport, which is in zone C and thus not covered by tickets for zones A and B. To get to the airport, you can buy a slightly more expensive ticket for zones ABC, or if you already have one valid for zones AB, you can extend its validity to zone C by buying an Extension Ticket (Anschlussfahrausweis).
Participants who are not speakers (including those who are receiving financial support) are requested to arrange their own accommodation, e.g. by searching booking.com or similar portals for hotels convenient to Hackescher Markt. You will want to book your stay starting from the night of Friday August 25 (if attending the precourse) or Sunday August 27 (if not). Since the workshop ends around midday on Friday September 1, you should be able to depart on that day unless the available travel options force you to stay until Saturday.
While there are no particular hotels being used to house large numbers of participants for this workshop, we provide below a list of hotels that we have used for similar events in the past. This is just for your information, in case it is helpful; please note that we have not checked whether most of them have availability or reasonable prices for the desired dates.
Hotels in walking distance of Hackescher Markt
Hotels in other areas of Berlin
Motel One Berlin - Hauptbahnhof (S-Bahn Hauptbahnhof, Mitte)
Meininger Hotel Berlin Hauptbahnhof (S-Bahn Hauptbahnhof, Mitte)
Meininger Hotel Berlin East Side Gallery (S-Bahn Ostbahnhof, Friedrichshain)
Meininger Hotel Berlin Tiergarten (U-Bahn Turmstr.)
Motel One Berlin-Potsdamer Platz (U-/S-Bahn Potsdamer Platz)
Hotel4Youth am Mauerpark (U8 Bernauer Str., Mitte)
Metropolitan Hotel Berlin (U3 Augsburger Str. or U3/U9 Spichernstr., Wilmersdorf)
Novotel Hotel Am Tiergarten (S-Bahn Tiergarten)
Novum Hotel Aldea Berlin (U2 Bülowstr., Schöneberg)
acama Hotel + Hostel Kreuzberg (U1/U6 Hallesches Tor, Kreuzberg)