Bridge over Wetlinka river

During a mountain trip we stopped for a moment on a small bridge over the Wetlinka stream. I noticed a wasp holding a piece of leaf. I didn’t know that it is possible for a wasp to collect things like for example leafs. But definitely the wasp took it to its burrow. The burrow was, I suppose, in the railing of the bridge. The wasp tried to go in though a hole in rusty weld. It tried many times without any effect because the leaf was to heavy, but finally it succeeded and disappeared in the railing.