![Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as \](http://www.ecns.cn/hd/2019/04/19/4b382079b02947a1a5f6dab6873bb35b.jpg)
Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as "Blue Forest", where bluebells bloom around mid-April and form a blue carpet. (Photo/Agencies)
![Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as \](http://www.ecns.cn/hd/2019/04/19/76250e3b5d8b42cbacb8b8e57859965b.jpg)
Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as "Blue Forest", where bluebells bloom around mid-April and form a blue carpet. (Photo/Agencies)
![Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as \](http://www.ecns.cn/hd/2019/04/19/3db0edd9c07142a3b94eccaa5593b31a.jpg)
Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as "Blue Forest", where bluebells bloom around mid-April and form a blue carpet. (Photo/Agencies)
![Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as \](http://www.ecns.cn/hd/2019/04/19/a0179e0068164aeaa0c04ba96b4e33db.jpg)
Photo taken on April 18, 2019 shows wild bluebells in the Hallerbos, near Brussels, Belgium. The Hallerbos is also known as "Blue Forest", where bluebells bloom around mid-April and form a blue carpet. (Photo/Agencies)