Bangladesh Bank, a uniface proof/specimen 500 taka, ND (1988), zero serial numbers, blue, lilac and multicoloured, the Tara Masjid in Dhaka at right in oval frame, signature of Chaudhuri low centre(Pick 30 for type, TBB B325b for type), a Giesecke and Devrient printing instead of the regular De la Rue who printed the standard issue. Maybe a trial printing?, uncirculated, mounting traces at reverse, unusual and very rare.
Estimate: £400 - £500