Collins
Slice cucumber thin. Juice lemon to get 3 ounces. Slice the remaining lemon thin. Reserve some lemon slices for garnish. Combine Pimm's, simple syrup, lemon slices and juice, half of the sliced cucumber and mint in a large container. Cover and refrigerate until flavors develop, at least 2 hours and up to 8 hours. Gently stir seltzer into Pimm's mixture. Serve in chilled collins glasses filled with ice. Garnish with extra lemon slice, cucumber slice, mint sprig, and strawberry.