People wave flags as the naval guided missile frigate Yuncheng (571) arrives at the Ngong Shuen Chau Naval Base in Hong Kong.  The frigate is open to the public as part of events celebrating the 15th anniversary of Hong Kong's handover to China. (Reuters)

Ken Livingstone, Britain's Labour candidate for London mayor, stands in front of a poster depicting London Mayor Boris Johnson as an alien, to launch Labour's new Ad Bus in south London. (Reuters)

People walk along the OCBC Skyway linking the Supertrees, that range from 25-50 meters in height and serve as vertical gardens in an area near Singapore’s busy financial district. The city-state is making efforts to nurture greenery and capture the essence of Singapore as a tropical city. (AP)

A man passes images of jailed opposition leaders on a wall in Barbar, Bahrain, west of Manama. Political leaders pictured from left are: Hassan Mushaima, Sheik Mohammed Habib Moqdad, and Abdulwahab Hussein. (AP)

Queen Beatrix of the Netherlands walks in a ticker tape parade during the annual traditional Queens' Day in Veenendaal. (Reuters)

Roger Lewis, with the Treme Brass Band, performs at a sunrise concert marking International Jazz Day at Congo Square in New Orleans.  Thousands across the globe are expected to participate in celebrations, including events in Belgium, France, Brazil, Algeria and Russia. (AP)

The sunrise reflects on buildings, including One World Trade Center, center left. One World Trade Center, which is being built to replace the twin towers destroyed in the Sept. 11 attacks, will lay claim to the title of New York City's tallest skyscraper Monday. (AP)

Pupils attend a class at El Mana islamique at Bori Bana, a slum in Abidjan, Ivory Coast.  The school, which teaches French and Arabic, houses about 200 pupils in three classrooms. The school fee for each pupil costs about $50 per year. (Reuters)

Laborers have lunch at a construction site in Sidon, southern Lebanon, ahead of May Day. (Reuters)

A man uses a machine to harvest tulips in a field in the northern German city of Schwaneberg. (AFP)

Horses enter and leave the race track in the early morning at Churchill Downs in Louisville, Kentucky. The historic track will host the 138th Kentucky Derby on Saturday. (AP)

French shoe designer Christian Louboutin opens his first-ever retrospective exhibition at the Design Museum in London. The exhibit showcases how Louboutin has helped transform the design of the shoe over the past 20 years. (AP)