Tens of thousands of people are expected to take part in a landmark European gay rights rally in Poland's capital Warsaw.
It is the first time the annual EuroPride parade is being held in Central and Eastern Europe.
The event has attracted controversy in staunchly Roman Catholic Poland.
Several counter-demonstrations have been scheduled to coincide with the parade in the city.
Warsaw's authorities have also received a petition with more than 50,000 signatures from anti-gay groups demanding the event be cancelled.
The EuroPride parade's organisers say they expect a minimum of 20,000 people from across Europe to take part in what should be a noisy and colourful event.
This is huge by Polish standards but small compared with more than a million people who attended the march in Madrid three years ago, the BBC's Adam Easton in Warsaw reports.
Our correspondent says that is partly because it is so much more difficult to be openly gay in Poland, where both the influential Roman Catholic Church and politicians regularly say homosexuality is not normal.
In a recent survey, almost two-thirds of respondents said homosexual couples should not be open about their sexuality.
It is extremely rare to see gay couples holding hands even in Warsaw, the country's most cosmopolitan city, our correspondent says.
Those who do face verbal or physical violence, such as Ryszard Giersz, 25, from a small town near the German border.
He won a small amount of damages in court last year after neighbours repeatedly verbally abused him and threw tomatoes and stones at him.
Such behaviour is common in Russia, where gay pride marches are often banned and anyone attempting to defy a ban face arrest, our correspondent adds.
BBC News
