A wooden city on bridges shouldn't last long, especially in a hot and humid environment like Crezchnoviy, a tropical lagoon in the Fianyarr world. Some people assume that it's magic that keeps the wooden structures standing but it's just dedication on behalf of the residents.
The people here like the taste of the creatures that dwell in the lagoon but the water is too dangerous to swim in for prolonged periods of time so structures were built out across the water to allow the locals to get to all of the different places, dive in to get what they need, then hop out again.
Naturally some people wanted to live close to work and people set up homes and then shops and then marketplaces on the bridges. Soon enough there was a big old rickety city sprawling across the walkways, just waiting for a storm to knock it all over and plunge them into the deadly waters.
Luckily that hasn't happened yet as the lagoon is sheltered within a gulf. So the buildings still stand. And people still live out their lives in them, decorating the ward with beautiful carvings and colourful sea shells, covering the walkways with wind chimes and woven reed mats, using boats made of local wood to take shortcuts beneath the high pilings of some of the bridge sections during low tide.
So what makes the waters so dangerous anyway?
The same thing that encourages such unique and tasty seafood-to-come to live down there.
The water has its own magics that repels outsiders by slowly increasing the temperature of the water around them, eventually boiling them alive until they are reduced to their essential salts. People have about a five minute window of opportunity to get in, grab the food and get out before the temperatures start becoming uncomfortably hot. As soon as the diver resurfaces and gets out of the water, the air steams off the protective magic which causes a hazy aura. The person must wait until they are dry before attempting another dive, lest the cumulative magic boil them too soon.
Visitors come from all around to enjoy the food and bring it back to the nobility of their realm and thus the seafood is the city's greatest exploit - alongside the shell jewellery and wood carvings. There are exotic coral reefs that only grow here where the freshwater meets the saltwater and is imbued by such potent magic and thus visitors can witness how the sunlight hits the clear blue waters to reveal the multicoloured decorations below. While coral reefs beneath a city would normally be spoiled by sewerage and waste, this area seems to have an additional benefit due to the protective magic. You see, the protective magic works on anything, including any waste that is tossed into the water, causing this to be the cleanest city in the world. The only mess that lasts is the local woods, discarded shells and bones, and other local products.
So people patch up the wooden structures (local stone is in short supply here and foreign stone would be eaten away) using the local forests that are protected and harvested in special ways to ensure that the few species of trees that the lagoon recognises as local don't go extinct. They deal with the constant damp, the splinters, the creaking floorboards and the sometimes swaying off the structures in strong wings, in order to live above a food supply protected by lagoon that would destroy them if they spent too much time within it.
The nobility and visiting rich folk (many of which come on pilgrimmages as they believe the waters will cure diseases) stay in mansions built ashore upon and just behind the sand dunes while the majority of the locals live, work and die on the weathered walkways, maneuvreing canoes and small boats built of local timber to spear food and trade with the merchant vessels that dare not enter the lagoon and thus weigh anchor a safe distance away.
The citizens are a brave and smiling lot who believe that their city is the prettiest in the world and who take pride in living above such a dangerous and fickle place. They believe that the offerings they make to the spirits and their cultural customs will keep the dangerous storms away. They believe that no storm will ever wreck their town, which is probably the only reason they live there, for should a savage storm break their bridges and drop their homes into the water, there will be many mutilated and maimed folk whose limbs dangled into the water for too long, and plenty of dead bodies turned to steam who couldn't find a dry place to hide.
Those who are renowned divers tend to tan with a slightly golden colour while those who boat often gets bands of golden tanned skin across their hands and legs and feet where water has most often splashed them. There doesn't appear to be any permanent longterm side effects. Yet.
And thus is this city known as the City of Marvels. Unique and exotic in all the lands.
Let me know if you ever use this small city in any of your games. I'm always curious to see my if my imaginings take root in someone else's head.