Answer:
The interest is cycling.
Step-by-step explanation:
Cycling is a sport that is widely practiced around the world. However, competitively, only a handful of countries have had good performances in major competitions like the Tour of France. These countries are mainly located in Europe, plus a few in the Americas, like the United States, and Colombia. This answers the first geographical question: where?
The second question "why there"? needs further analysis to be solved. One can see that successful cycling countries like the Netherlands and Belgium have top quality cycling infraestructure. In the Netherlands in particular, biking lanes are spread all over the country.
The case of Colombia is also interesting, because it is a developing country that does not have as much wealth as the Netherlands or Belgium. One can see that in Colombia, a special form of cycling is popular: highland cycling, and this gives Colombian cyclers a particular advantage in highland stages of major cycling competitions.