This followed an advanced implementation of an agreement by European Union leaders, during ratification of the Nice Treaty, to do so at such a time as the total membership of the EU surpassed 18 Member States. Prior to this, summits of the European Council were based in the EU member state that held the rotating Presidency of the Council of the EU. A number of renovations were made to the building to accommodate the increased demands of both institutions and growing EU membership, including the conversion of the building's basement car park into additional meeting rooms.