The Wave-Gotik-Treffen (WGT; German for "Wave Gothic Meeting") is an annual world festival for "dark" music and "dark culture" in Leipzig, Germany. 150+ bands and artists from various backgrounds (gothic rock, EBM, industrial, noise, darkwave, neo-folk, neo-classical and medieval music being examples) play at several venues throughout the city over four days on Whitsuntide. The festival also features multiple all-night dance club parties, several fairs with medieval, gothic, and related merchandise, a variety of cultural exhibitions and performances, large themed picnics, and a number of unofficial fringe events.

https://en.wikipedia.org/wiki/Wave-Gotik-Treffen

https://www.wave-gotik-treffen.de/english/

The next two are in German, but if you read them thru a web browser, most automated translators do a good job:

https://www.mdr.de/kultur/wgt/wave-gotik-treffen-leipzig-highlights-ueberblick-100.html

https://www.mdr.de/kultur/wgt/index.html