The A340 was the first plane where I became aware of the crew rest, because there was a downstairs area with passenger lavatories and also the crew rest behind

The A340 was the first plane where I became aware of the crew rest, because there was a downstairs area with passenger lavatories and also the crew rest behind another door, it was labeled as such. It's a weird layout though, because in order to make headroom for the downstairs, it blocks out some seats 'upstairs'.