Complex sentence: It used to host a regular concert series the'late mix', but this has since disappeared into a certain Norman Foster designed cultural black-hole that is believed to be somewhere on the Gateshead Quayside.
Split into simpler sentences: It used to host a regular concert series: the'late mix'. But this has since disappeared into a certain Norman-Foster-designed cultural-black-hole that is believed to be somewhere on the Gateshead Quayside.