Since St. Kitts and Nevis established the world's first citizenship by investment programme (CBI) in 1984, scores of countries worldwide have gotten in on the act and generated billions of dollars, either by launching straight CIPs, or residency by investment programmes (RBI) aka "golden visas" as a backdoor to citizenship. We take a look at 46 countries that offer these schemes, how much they cost and the myriad benefits they provide, and reveal why they are so controversial.