Hendrick de Keyser's last great design, the Westerkerk was completed in 1631 beside the Prinsengracht, and its tower — the tallest church tower in Amsterdam, crowned with the imperial crown of Maximilian I — has been a fixed point of the city ever since. Rembrandt was buried in the church in 1669, in a grave that was never marked. The interior is plain in the Protestant manner, a long unbroken volume with an organ of the seventeenth century, and its acoustic has made it a concert space as much as a place of worship: oratorio, choral music and opera in concert are heard there throughout the year.