Trinidad and Tobago
Trinidad and Tobago is a hot, humid jungle nation with year round rainfall. Countless waterfalls and creeks run down from mountains that receive as much as 150 inches of rain per year.
No canyoneering expeditions have ever occurred here. But that doesn't mean there aren't any canyons! Potential for several five-star routes exists. The best potential is probably in the drainages around Mt. Aripo, although there are certainly others. Start by looking a satellite maps, and go from there.
Locals are EXTREMELY disinterested in hiking or outdoors, in general. Hunting (and illegal poaching) is more widespread. Although hunters are responsible for the decimation of certain endemic flora and fauna, like ocelots, they're probably the only ones that know the jungles well. They cut and maintain trails for miles and miles in forests that no one else goes to. As such, contacting hunters to ask about slots would be well worth the effort to find canyons.
Canyons may be limestone, granite, or other. The main known limestone area is the area from Mt. Aripo heading east for a few kilometers. In this region, there are about a dozen known caves, and likely several hundred or more entrances that have never been entered. The potential for decent caves here is also high, and - you guessed it - Trinidad has likely never had any type of caving expedition.
The dangers here, aside from the usual street crime in Port of Spain, are snakes and scorpions. There are multiple venomous species, which can hide in rocky crevasses and under logs. It's probably a good idea to wear boots to protect from snakes. There are also some small wasp nests found in some parts of the jungle, but no more so than any other Caribbean region.
Overall, Trinidad remains a frontier for canyon and cave exploration.