According to the Adventure Travel Trade Association, travellers spent $263 billion on adventure travel in 2012, up from $89 billion in 2009. Adventurous destinations and activities are certainly trending right now, according to Travel Pulse. Here's a selection of up-and-coming ideas in this space:

Travel by bike
Several travel companies are providing their customers with the chance to see interesting locations either partially or entirely by bicycle. Whether it's a combination cruise and bike trip or a complete bike tour through Vietnam and Laos, these journeys have strong appeal.

Food trips
Sometimes, adventure travel means nothing more than a really authentic experience. This is the case with travel to destinations known for their food culture, according to WTOP. Travellers are interested in seeing how pasta is made in Italy, or cheese in Switzerland, and can even put together tours that encompass quite a few different types of food.

Total silence
Perhaps the biggest and most unusual luxury travellers can find these days is silence and time away from the perpetual connectivity of modern life. Finland, for example, is highlighting its quiet, remote nature in its tourism materials, while some other destinations boast that there's ample time for quiet reflection to be had there.