Many cities have regular big cultural and sporting events, which draw tens of thousands of participants and lock up accommodation and transport; but it’s generally just for a day or so. Those listed here are really really big events, which may draw millions, locking up not just the city but much of the country over an extended period. If you aim to be there, especially as an independent traveller, you must plan over a year in advance. If you’re not interested in the event itself, come another time, perhaps a few months later when the place has returned to normal but all the new infrastructure and amenities are there for you. What you can't do is dabble, going to the area thinking you might sort-of drop in on the event, as mega-crowds will be ahead of you.
Big sports tournaments are synchronised with the four year Olympic cycle, so dates and venues are usually announced that far ahead.
23 June - 23 July 2023: FIFA Africa Cup of Nations, Côte d'Ivoire. This soccer tournament doesn't draw the size of crowds seen in Europe, but they're sure to overwhelm the host country's limited accommodation, transport and other facilities. 24 national teams will participate, and the venues are expected to include Abidjan (which has the old and the new national stadiums), San-Pédro, Yamoussoukro, Bouaké and Korhogo.
26 June - 1 July 2023 (1444 AH): Hajj in Mecca. The key pilgrimage in Islam, drawing some 2 million registered pilgrims. Another million may attend unofficially, as they live in the region and don’t need visas. Most pilgrims also visit Medina 450 km northeast.
1 - 24 July 2023: Tour de France is the world's premier on-road men's cycle race. In 2023 it starts in Bilbao and tours the Spanish Basque region for three days, then continues across France to culminate in Paris. This is a huge event because of the size of the sporting and commercial entourages, and the roving audience. Especially in the mountains with only a single connecting road, whole areas become locked down, and even fire trucks struggle for access. Giro in Italy in May and Vuelta in Spain in Aug / Sept are locally disruptive but on nothing like this scale. The conclusion of the men's race in Paris is also the start of the women's Tour, held over a week - this likewise is a much smaller affair.
20 July – 20 Aug 2023: FIFA Women’s World Cup in Australia and New Zealand. Hitherto this tournament for women’s national soccer teams was a modest affair, but 2022 saw a big lift-off in the audience for the women’s game, and professional development of those within it. So the size of this event will indicate whether that boost is permanent. 32 teams are taking part. The host cities are Sydney, Brisbane, Melbourne, Perth, Adelaide, Auckland, Wellington, Dunedin and Hamilton. (The 2026 host country is to be decided in summer 2024.)
8 Sept - 28 Oct 2023: Rugby Union World Cup in France, with 20 men's national teams playing. The matches are in Paris, Marseille, Lyon, Lille, Bordeaux, Saint-Étienne, Nice, Nantes and Toulouse.
12 Jan - 10 Feb 2024: the 2023 AFC Asian Cup in Qatar, with 24 men's national soccer teams competing. The venues are tbc, but probably the same as those used for the World Cup in 2022.
14 - 19 June 2024 (1445 AH): Hajj in Mecca - because it follows a lunar calendar (not a solar-lunar calendar like Easter), it falls 10 to 11 days earlier each year.
14 June - 14 July 2024: UEFA Euro Finals across Germany. 24 national soccer teams will compete, playing in Berlin, Munich, Dortmund, Gelsenkirchen, Stuttgart, Hamburg, Düsseldorf, Cologne, Leipzig and Frankfurt. Just over a million attended the covid-blighted 2020 Finals (postponed to 2021) so the audience of 2024 will probably be much greater. Fans know where their own team will play in the early stages, but the varied fortunes of the tournament mean they don't know their later venues. So this creates a huge travelling army trying to book last-minute accommodation and transport to cities the far side of the country. (The 2028 host country is to be decided in late 2023.)
29 June - 21 July 2024: Tour de France starts in Florence and tours Italy for three days; on Day 4 they cross the Alps to continue across France. The 2024 Tour is a week earlier than usual, and - uniquely - ends in Nice not Paris, to avoid the capital on the eve of the Olympic Games.
26 July – 11 Aug 2024: Summer Olympics (XXXIII), Paris. The concept is that Olympics are hosted by a city, not a country. The reality is that they embroil the nation, especially with such a central metropolis and transport hub as Paris. There are also events in Lille, Marseilles, Lyon, Saint-Étienne, Bordeaux, Nice and Nantes, and you'll need to set off especially early to watch the surfing. That's at Teahupo'o in Tahiti, 15,716 km from the host city. (The host of the 2028 Summer Olympics, Los Angeles, is a whole lot closer.)
June / July 2025: FIFA Africa Cup of Nations held in Guinea, with 24 teams competing. Dates are not confirmed, the likely host cities are Conakry, Kankan, Labé and Nzérékoré. (The venue for 2027 is not yet decided.)
6 - 22 Feb 2026: Winter Olympics (XXV) in Milan, Cortina d'Ampezzo and half a dozen other resorts in the northeast of Italy. This area is well developed for visitors and has fairly reliable snow. (The 2028 host city is not yet decided. Bids are likely from Barcelona-Andorra, Sapporo, Vancouver-Whistler and Salt Lake City.)
8 June – 3 July 2026: FIFA World Cup Finals in the USA, Canada and Mexico. This is the top soccer tournament for men’s national teams, with 48 nations participating. The three host nations automatically qualify, and the others will be known by the end of 2025. There are 16 host cities, grouped into three divisions to reduce travelling distance somewhat, but everyone involved will still have to cover a lot of ground. The three are Vancouver, Seattle, San Francisco, Los Angeles, and Guadalajara in the Western Division; Kansas City, Dallas, Houston, Atlanta, Monterrey, and Mexico City in the Central Division; and Toronto, Boston, New York City, Philadelphia, and Miami in the Eastern Division. (The 2030 host country will be decided in 2024.)
It is quite remarkable how little illness, accidents or crime is recorded at mega-events such as the Olympics, considering their huge and not always sober audiences. Partly that's under-reporting but it also reflects the security that cloaks the event, and an inherently healthy set of travelers. Standard advice about care of valuables and avoiding drunks, low-life and traffic should see you through.
The game-changer in 2020 and 2021 of course was the COVID-19 pandemic. It's difficult to say how this will play out over the coming years; but if anything could spark a resurgence, it would be huge crowds like the 60,000-plus in London's Wembley Stadium for the Euro 2020 Finals. Even if they were minded to, those people couldn't "social distance" in the stadium, nor in the congestion around the stadium, on public transport, in pubs or in outdoor big-screen viewing areas. And the problems start well before you arrive, since you must plan and book well in advance, yet the event may be cancelled or the host country not let you in or impose onerous conditions. Big multi-national events can only be as safe as the participating nation with the weakest covid-control.
In less developed places, consider the conventional risks of crowd collapse (as at Hillsborough, Sheffield in 1989) or of transport catastrophes eg through over-crowded ferries capsizing.