Construction of Gdynia seaport was started in 1921, but because of financial difficulties was conducted slowly and with interruptions. It was accelerated after the Sejm (Polish parliament) passed the Gdynia Seaport Construction Act on 23 September 1922. By 1923 a 550-metre pier, 175 metres of a wooden tide breaker, and a small harbour had been constructed. Ceremonial inauguration of Gdynia as a temporary military port and fishers' shelter took place on 23 April 1923, and the first major seagoing ship arrived on 13 August 1923.

http://en.wikipedia.org/wiki/Gdynia

This picture is taken from the ferry going to Trelleborg, Sweden