The Burcht van Leiden, also known simply as "De Burcht," is a historic mound located in the city of Leiden, Netherlands. Here's some information about it:

1. **Location:** The Burcht van Leiden is situated in the heart of Leiden, near the center of the city.

2. **History:** It is one of the oldest extant structures in Leiden, dating back to the 11th century. The mound was constructed as a defensive fortification, providing a vantage point for monitoring the surroundings and as a refuge for the local population during times of danger.

3. **Appearance:** The Burcht is a circular earthen mound with a diameter of approximately 35 meters (115 feet) and a height of about 9 meters (30 feet). It is surrounded by a moat and offers panoramic views of the city.

4. **Access:** Visitors can access the Burcht and climb to the top to enjoy the views. The entrance is through a gatehouse.

5. **Purpose:** Today, the Burcht serves as a historic site and a symbol of the city's rich history. It's a popular spot for tourists and locals alike to visit and appreciate both its historical significance and the scenic views it offers.

6. **Events:** Occasionally, events and exhibitions are held at the Burcht, and it is also a picturesque spot for picnics and leisurely walks.

If you plan to visit Leiden or are interested in its history, the Burcht van Leiden is definitely worth exploring.