If you are interested in learning more about all strange wedding cultures then the best way for you to do so would be online through the various websites that feature this as well as many other categories of cultural practices that could be considered as being strange.
It depends upon which website you refer to for a range of strange wedding cultures as different websites would be featuring different types of cultural practices so you might want to be specific with what you might actually be looking for. In the western world, you might be used to official wedding practices which would more or less look like a business meeting as opposed to something of a cultural nature.
In other parts of the world however, you will find weddings taking place in a totally different way including certain practices that you may find both intriguing as well as strange at the same time.
It is important to not mock or ridicule such practices as everything happens for a reason and all sorts of strange wedding cultures that you see featured in videos as well as other forms of content online have some history associated with it.
Developing countries would have their own set of wedding cultures that they practice, some of which might be quite strange to someone from the west to positively digest.