royal greenhouses at laeken

They only allow public access for about two weeks every year, and pretty much all the tickets go to tour operators... but I might need some verification on that last point.

I visited the Greenhouses in 2008 and it was great. I don't think I got tickets ahead of time. I remember trying to call ahead of time but no one spoke English. Pretty sure we just showed up and got tickets "at the door." If you are relying on public transportation plan accordingly. I remember a metro ride past the Atonium and a bit of walking but it was well worth it. Good luck.

The website suggests that tickets can't be purchased in advance, so I suspect that they won't "all be going to tour groups". Expect long queues as a result though. According to the site, the greenhouses are open this year Tue-Sun from 19th April to 12th May, and Tuesday 23rd April is reserved for people with disabilities and their carers.

Unless what Tom means is that tour groups are sending people to camp outside the ticket office overnight and buy a hundred tickets as soon as it opens...

My source on that was my father-in-law, but he may have just made an assumption...