Around the world trip, is there a way to simplify the visa gathering?

The keys to solving visa problems on such long trips are (a) planning/research and (b) getting visas on the road, as you travel. Getting visas to “all the countries in the world” in one shot and then embarking on a trip is just not realistic.

• First, take a look at http://en.wikipedia.org/wiki/Visa_requirements_for_Belgian_citizens
• Note that for Belgian citizens, only a handful of countries require visas. The rest either don’t require a visa, or have a visa-on-arrival process, or require some sort of easy-to-get electronic permit which you can apply for online, etc.
• Pay close attention to the fine print for these “visa-free” and “visa-on-arrival” countries. For example, do you have to arrive via a particular entry point (typically the main airport in the capital city) to get the VOA? Do you have to have onwards tickets? What’s the maximum stay? Aside from the Wikipedia link above, this is a good source of information if you’re travelling by air: http://www.iatatravelcentre.com/
• For any countries that do require visas, find out where you are allowed to apply for them. Some countries are easy (e.g. you can get a Chinese visa pretty much anywhere in the world as long as you meet the requirements, like onwards tickets), while some countries may actually require you to apply in your home country. Plan your trip accordingly.
• Sometimes, even if you can’t get a particular visa in a foreign country, you may be able to mail your passport back to the country’s consulate in Belgium for a visa (or better yet, to a visa agent in Belgium which will handle the consulate interaction for you). Of course, mailing away your passport while in a foreign country is never fun (or cheap), so use this only if absolutely necessary.
• Keep timing in mind. Some visas you can only get between X and Y days before your intended trip, so you must time your visa application correctly.
• Keep in mind that some visa application processes elsewhere in the world may not be what you’re used to. Be ready for crazy/inconsistent requirements, long processing times (processing time = “whenever the consular officer feels like taking a look at your file“), even bribe requests, etc. I’ve had some pretty unusual visa application experiences and have heard of even crazier ones. Read about people’s experiences online, and if a given visa process is particularly crazy, apply for that visa in Belgium since the process in your home country will likely be the easiest and most efficient one.
• Keep passport space in mind. You may need to go through several passports to have enough space for all the visas and stamps, and many countries require 2 blank pages before they’ll issue a visa. I don’t know the rules in Belgium – you may need to go back in the middle of the trip to change your passport. Don’t be shy telling immigration officers around the world to conserve passport space (tell them which page you’d like the stamp on).
• There are lots of other nuances as well, e.g. the ability to enter countries more than once in a short period of time (e.g. this can be an issue with India), requirements to have a booked tour (Bhutan), the need for an official “invitation” which can typically be arranged through a 3rd-party company (e.g. ex-Soviet countries), etc.

Basically, either do lots of detailed planning (if you have a fixed amount of time and know in advance what you’d like to see), or just take a more relaxed approach, learning as you go, getting visas as you go, but knowing that you may run into unexpected problems and may not hit every country you may want. Personally, having tried both approaches, I think the latter approach is more fun for super-long trips, and you can’t plan for everything anyway.

The main way to simplify this process is to use the services of an agent. There are a few that specialise in this and you would want to vet them a bit before putting your money, passport and credibility in their hands so I am not going to name any. But I heard about a handful that would for example arrange visas for Russia and many central Asian countries as a “package” (you provide an itinerary and your passport and they arrange invitations, send your passport to the relevant consulates for you, etc.)

As a Belgian citizen, if you do not want to go to Sub-Saharan Africa and the Middle East, this area (central Asia and the former Soviet Union) is probably the most troublesome. You will need a visa or some formalities in advance for ten or twenty other countries (India, China, North Korea, Iran, Belarus, Vietnam…) but you are lucky enough to be able to visit most of the world with little or no formalities (Europe is wide open without so much as a concern about overstaying in the Schengen area, the Americas are visa-free for you and many South-East Asian countries merely require a visa-on-arrival which is easy to get without any trip to an embassy beforehand).

The thing is is that, outside the Schengen area, visas are entirely each country’s prerogative. Nobody can issue a “global” visa, it’s not a mere technical issue but fundamentally at odds with the way international law and passports/visa work. One way or the other, you must obtain an authorisation to enter from each country you want to visit so having someone secure them for you one-by-one is the best you can do.

In fact, trips to various consulates are not the main difficulty with getting visas for a round-the-world journey. The main issue if you want to do it all at once and in a short time is that you often cannot get visas more than 2-3 months in advance and will often have to wait for them (at least of few days, possibly weeks) so that getting all the visas all at once before the journey might be impossible. It might also be difficult to apply from a country where you are not a resident, meaning you can’t always get what you need on the road and might therefore need to return to Belgium once or twice in the middle of the trip.

Beyond visa-free travel, your location and citizenship have a few other advantages. It’s (much) more expensive but Belgium offers special passports with more pages and tend to issue them quickly, which would ease the process. And with the European institutions and everything, many countries have a representation in Brussels so at least you don’t have to travel very far to find their nearest consulate (according to Wikipedia, there are 185 embassies in Belgium more than in Paris, Berlin or London; by comparison Greece has 80 or so and Malta has only 20).