The top award among the 65 countries and 100 studios participating has gone to a Swiss display focused on optimal living quarters. The theme of this year's show in Italy's La Serenissima is Freespace.
For the next six months, the International Architecture Exhibition with participants from all round the world is set out in pavilions and spaces across the city built over 118 islands at the northern end of the Adriatic.
Entitled "Svizzera 240: House Tour," the Swiss entry which won the top prize Golden Lion Best National Participation as the show opened on Saturday was designed by Alessandro Bosshard, Li Tavor, Matthew van der Ploeg and Ani Vihervaara.
The optimal height for living space is 240 centimeters (7 feet 8 inches), and the empty Swiss flat with those measurements was designed so visitors can walk through it.
A Golden Lion for lifetime achievement was awarded to British architect and historian Kenneth Frampton.
The German entry "Unbuilding Walls," looks at construction work along the site of the former Berlin Wall which divided the old East and West of the city that is now the country's capital.
Irish architect Shelley McNamara, co-curator with Yvonne Farrell of the main exhibition "Free Space" said: "We have to be aware of the political issues in order to make buildings which protect, in so far as we can, the status of the human being in the world."
Saudi Arabia is participating for the first time with a display of urban sprawl in Riyadh, Mecca, Dammam and Jeddah. Curator Sumayah Al-Solaiman said "The sprawl is the result of the oil boom but the result of the sprawl is actually social isolation."
Also participating for the first time, The Vatican asked world-renowned architects including Norman Foster to create ten chapels in a wooded area on one of the islands in the Venetian lagoon.
The exhibition runs until November 25 and includes five other countries participating for the first time: Antigua and Barbuda, Guatemala, Lebanon, Mongolia and Pakistan.
jm/msh (AP, dpa)