A new £3.5m visitor and education centre at a nature reserve in Cambridgeshire opens on Monday.
The Wildfowl and Wetlands Trust in Welney has been built using environmentally-friendly techniques and energy saving technology.
The two-storey building includes a multi-purpose area for meetings, business and community use and display space for arts and crafts.
The reserve was closed last month to train staff to use the new facilities.
The wetland reserve, on the Ouse Washes, is home to winter gatherings of swans.