The Marimetsa bog hiking trail is a 9-kilometer-long trek that makes for a perfect full-day trip from Tallinn. The hike itself typically takes 4-5 hours. While there are stretches of boardwalk, it can be wet in places, so come prepared.
While not impossible to reach by bus, it's more convenient to get there by car. Driving can take up to an hour and a half, and there's a parking lot at the trailhead.
If you still have energy after your hike, you could head on to Haapsalu for dinner or hit up Rummu Quarry, the final spot on our list, on your way back to Tallinn.