Vantaa is actually the name of a river, at whose mouth the old city of Helsinki was built in 1550. There's a couple of nice spots where you can walk along the Vantaanjoki and watch its meanders, rapids, abruptly changing speed or, in winter, partly frozen surface.
One is at the junction of Road n.3 (the motorway to Tampere) and the Ring III. That's where I took the pic.
The Kerava River is passing through here, a nice river with lots of plantations around, birds & fish as well. There are some spots you can even go and swim in the river.
Vantaa is a large area city that actually made of many villages gathered together as municipality. There are still many old farms and fields around and some people here still living from agriculture.
This place is on the east of Vantaa, small lake where you can swim all year around even in the winter when the late is frozen. How come? Want to see more? check the travelogues.