CAMBRIDGE — For 71 years since World War II, those who lost their lives in the line of duty have been honored on Memorial Day in Cambridge.

On Monday, a solemn wreath-laying ceremony was held at the World War I Memorial Fountain at Long Wharf Park. The Rev. R. George Ames Jr., himself a veteran, opened the ceremony with a prayer.

“Remember all the veterans that gave their service, whether they were officers, enlisted, or whatever duties they might have had,” The Rev. Ames said. “Oh God, as we pray today, we think of those veterans that are homeless, don’t have proper medical care, and we call on our Congress people to remember the veterans and to do the job that they should do for us.”

Bob Tieder, a veteran and five-time past commander of American Legion Post No. 91 in Cambridge, welcomed the many city, county and state officials, and guests.

“Ladies and gentlemen, we observe this day with heavy hearts, but hearts filled with gratitude for our country’s brave servicemen and women who laid down their lives for their country,” Mr. Tieder said. “Truly, this holiday belongs to them. ... Let the world know that we intend to remain strong and free, and do me and yourself a favor. The next time you see a man or woman in a United States Armed Forces uniform, take time to thank them. Let them know that you are proud of them and the service they’re giving to our country.”

Wreaths were laid to honor the many veteran and civic organizations that support the commemoration, as well as the fallen. Mr. Tieder drew special attention to the wreath dedicated to the SS Dorchester. The wreath, laid near Cambridge Creek, honors the service members who lost their lives when the SS Dorchester was torpedoed by a German U-Boat while on its way to Greenland during World War II. According to Mr. Tieder, there were 902 men aboard the troopship and 668 of them died when it sank.