#26 - However, in particular cases, it can pay off to build earlier Wonders of the World. For example, if you find yourself in a small island, you'll benefit a lot from Lighthouse for speeding up the maritime discoveries. Also, if one of your cities is really good at Trade, the Colossus will boost your technology rate. Even better if you later combine it with the Copernicus' Observatory, some good trade routes, a Library+University and a Marketplace+Bank (in this case it will compensate to build the improvements). #27 - After discovering Writing and Trade, you should go for Navigation. Don't waste your time and money building Trireme units unless there is another continent quite close to yours. Instead, wait for the ability of building Sail units (with Navigation) to start the maritime discoveries. #28 - Don't be greedy when you find a hut in your own continent - if barbarians are inside, they can really annoy you, destroying your units or even capturing or destroying unprepared cities. If the hut is close to one of your cities, wait until it is properly defended, before entering the hut. Besides, move away any vulnerable units, like Caravans, Diplomats and Settlers.