FUJIFILM X-E3|9MM|ISO200|4 minutes|F8

Long exposure photography indeed produces spectacular result.
You need a right tool to take long exposure photos. To expose you photo beyond 30 sec or 1 minute, you need natural density (ND) filter. Most famous is ND1000 which provide 10 stops of exposures.
Price of these filter cost a bomb.
Here are some good brand and its approximate prices:
1) Lee Filter (Square 100mm) – RM600 (USD150)
2) Hitech (Square) – RM800
3) SingRay (Square 100mm)- RM1500 (USD400)
4) Hoya Pro (circular 77mm)- RM360

Actually there are plenty budget filter from China.

I bought XCSource, the one that I used to capture above image, from China cost me RM43.00 (USD10).