I think it was made here, in Murano.
"Sommerso" glass is the related technique.
Seguso was probably the most famous glassmaker using that style, but many others make pieces very similar (formia, Oball, Tosi...)
I see no signature on the bottom. I suppose the production not very recent, due to now normally they feature an engraved signature.
Sincerely
Alex
www.artofvenice.com