@SWYV, the message you got was just a hidden chest that gave you three bombs. You need to use them to proceed.
Have you examined both switches? Each one corresponds to one bridge. You need to use a tool on one of the switches that gives you enough time to run back across the first bridge.
@mk1995: You're in the right place. You need to use something around you to help your tools get to the switch.
In case you have an older version (I added a sign in the newest one), you can read it here:
Sign wrote:
Beware large arachnids. They are quite harmless, but are known to construct sturdy, resilient webs.
The song in Moreina was custom made by Arcanum, I believe. It was actually intended for a "Village in the Mountains", but it works for my city as well, don't you think?
