In the disquieting period during and after the Baltimore riots, attendance at the Maryland Zoo plunged 59 percent. The zoo sent out a fundraising letter Friday depicting a single, lonely penguin: "We need you more than ever!"
At the Maryland Science Center, "on our first weekend back in business, our attendance was probably off by 70 percent or more," said Chris Cropper, senior director of marketing.
The yellow school buses that ordinarily idle outside the Walters Art Museum disappeared as field trips were canceled, contributing to a 7 percent drop in visitors last month compared to May 2014.
Revenue at Horseshoe Casino Baltimore dipped 4.4 percent from April to May, after tumbling 7.3 percent the month before.
The city's attractions have struggled in the aftermath of the riots that erupted April 27, the day of the funeral of Freddie Gray.
The institutions say visitors are gradually returning. But many attractions are trying to regain momentum after images of fires, looting and confrontations between rock-throwing rioters and police were broadcast around the world.
"In certain cases, the attractions are showing limited improvement from a month ago, but no one is seeing the numbers they'd like to see," said Kirby Fowler, president of the Downtown Partnership of Baltimore. "The year was shaping up to be a strong one. We need to promote the city as much as we can."
Among the attractions Fowler is monitoring is the popular National Aquarium. Attendance has been recovering week by week, spokeswoman Kate Rowe said, but the last week in May was still down 19 percent compared to a year earlier, and June has been "flat" so far.
During the 10-day state of emergency imposed by Gov. Larry Hogan, the zoo attracted just 9,733 visitors — less than half the 23,587 during the same stretch last year — and lost $150,000 in revenue.
"On the 28th [of April] we would probably have had 3,000 people," spokeswoman Jane Ballentine said. "We had 72."
Zoo officials were encouraged that the zoo's biggest annual fundraiser — a beer-tasting event on Memorial Day weekend — sold out.
"Will we see our numbers come back up? We certainly hope so," Ballentine said.
"Are the folks who would wake on a Saturday morning and say, 'It's a beautiful day, let's go to the zoo,' still going to come? That's hard to predict."
The zoo, like other tourist spots, was hurt when schools suspended field trips, a staple of spring.
The Anne Arundel County school district was one of several that canceled field trips into the city.
"We were pretty clear from the beginning that it was in the best interests of our students and staff just to avoid the potential that something could go wrong," district spokesman Bob Mosier said. While a family may make a personal choice to visit a potential trouble spot, Mosier said, that's different than dispatching ""40 kids on a school bus."
Many of the school trips were rescheduled.
"I went over today, and the buses were back on Centre Street and it was good to hear the laughter and the buzz," said Mona Rock, a spokesman for the Walters. Museum attendance fell to 15,718 last month from 16,900 in May 2014, she said.
The Science Center was also embracing a return to normal operations.
"Last weekend was the first weekend where we were on par with the same weekend the previous year," Cropper said.
Asked if there still might be lingering riot-related effects, he replied: "We're not in the fortune-telling business."
Downtown attractions are trying to push past not only the riots but also continuing violence in the city. The 42 homicides in May made it the deadliest month in the city in decades.
"The current homicide rates out in the media are there — there's a lot of things going on," Horseshoe general manager Chad Barnhill told the Maryland Lottery and Gaming Control Commission at a recent meeting.
Horseshoe, which opened last August, generated $21.9 million from slot machines and table games in May, down from $22.9 million in April.
Horseshoe, which is open 24-7 even on holidays, was forced to close for the first time when Mayor Stephanie Rawlings-Blake ordered a nighttime curfew to keep residents off the streets.
The casino said in a statement that it had been on track for its best month in April, but "the need to close for several consecutive nights during peak hours had a significant impact on our monthly revenues."
A challenge perhaps more daunting than the curfew is convincing out-of-towners that the casino area is safe.
Noah Hirsch, Horseshoe's vice president of marketing, said the casino is battling the "misconception that the events taking place are citywide when the casino district has been unaffected by any of those events."
Much of the rioting occurred in West Baltimore, but some downtown stores were also looted and vandalized. Horseshoe is in the Camden-Carroll area, on the other side of Oriole Park and M&T Bank Stadium from downtown.
The Orioles have seen fluctuating attendance since the riots, buoyed by a well-attended series last weekend against the Tampa Bay Rays. The club declined to comment on the impact of the riots.
Horseshoe is planning two weekends of free outdoor concerts — June 13 and 14 and June 27 and 28 — "really just to make sure folks know businesses are open in Baltimore and invite folks to come down who might not come down," Hirsch said.
Fowler, of the Downtown Partnership, said he is reaching out to marketing organizations such as Visit Baltimore — and to the attractions themselves — to coordinate messages designed to entice visitors back.
"For several weeks, everyone was trying to figure out how to adjust to the events that occurred," Fowler said. "And now people are ready to get to work."
Baltimore Sun reporter Jessica Anderson contributed to this article